Unit 2

Question 1

Describe absorption spectroscopy

Answer 1

• a spectroscopy is a spectroscopic technique that is used for measuring the absorption as it interacts with the sample. The radiation could be a function of either frequency or wavelength
  -related to the absorption spectrum because the sample used to interacts with electro magnitude radiation (EMR) in the form of photons from the radiating field

Question 2

Describe absorption spectrum

Answer 2

To the frequencies of light transmitted with dark bands when the electrons absorb energy in the ground state to reach higher energy states

Question 3

What does the intensity of the absorption depend on?

Answer 3

Differs depending on frequency and this variation is the absorption spectrum

Question 4

What provides the principle means of measuring analytes in biological fluids?

Answer 4

Interaction of EMR in the form of photons with matter

Question 5

Describe scattering of radiation

Answer 5

• transmission of radiation i n matter can babe viewed as a momentary retention of the radiant energy by atoms, ions or molecules followed by reemission of the radiation in all directions as the particles return to their original electronic state
• types:
  —Rayleigh scatter
  —Tyndall effect
  — Raman scatter

Question 6

Describe Rayleigh scatter

Answer 6

• light scatter by molecules or aggregates of particles with dimensions significantly smaller than the wavelength of the radiation
• examples: blue color of sky

Question 7

Describe Tyndall effect q

Answer 7

• occurs with particles of colloidal dimensions
• can be seen with the naked eye

Question 8

Describe Raman scatter

Answer 8

• involves absorption of photons producing vibrational excitation
• always varies from the excitation energy by a constant energy difference

Question 9

What light does spectrophotometric techniques use?

Answer 9

• ultraviolet or visible light

Question 10

Describe graphs of absorption spectroscopy

Answer 10

• percent transmittance versus concentration
• absorbance versus concentration

Question 11

Describe lamberts law

Answer 11

• states that for parallel monochromatic radiation that passes through an absorber material of constant concentration, the radian power decreases logarithmaically as the light path increases arithmetically

Question 12

What did lambert law prove?

Answer 12

• that for monochromatic radiation that passes through an absorber of constant concentration, there is logarithmic decrease in the radiant power as the light path increases arithmetically

Question 13

Describe Beer-Lambert law

Answer 13

• based on previous work by Lambert, Beer discovered that for monochromatic radiation, absorbance is directly proportional to the light path, b, through the medium and the concentration , c, of the absorbing species
  —> the work culminated in the Beer-Lambert law, or simple beers law
• concentration of the analyte in solution can be determind by several different methods based on the Beer-Lambert law

Question 14

What is the equation to show the relationship between transmittance and absorbance?

Answer 14

A = log1/T = log100%/%T = log100-log%T
A= 2 - log(v10)%T

Question 15

What equations can be used to determine the concentration of the analyte in a solution?

Answer 15

At= a x Ct x b
As = a x Cs x b

• At = absorbance of test
• As = absorbance of standard
• Ct = concentration of test analyte
• Cs = concentration of standard

Question 16

What are the 5 significant components in either a single- or double-beam configuration of a spectrophotometer?

Answer 16

1. Stable source of radiant energy
2. A device that isolates a specific region of the electromagnetic spectrum
3. A sample holder
4. a photo detector
5. A read-out device

Question 17

Describe radiant energy sources of a spectrophotometer

Answer 17

• provide polychromatic light
• must generate sufficient radiant energy or power to measure the analyte of interest
• two type:
  —> continuum
  —> line

Question 18

Describe the continuum radiant energy source

Answer 18

• emits radiation that changes in intensity vertically slowly as a function of wavelength

Question 19

Describe the line radiant energy source

Answer 19

• emit a limited number of discrete lines or bands of radiation

Question 20

Describe monochromators

Answer 20

• spectroscope modified for selective transmission of a narrow band of the spectrum
• quality of a monochromator is described by:
  —> normal wavelength
  —> Effective bandwidth
  —> Bandpass
  —> Filters

Question 21

Describe normal wavelength

Answer 21

• wavelength in nanometers at peak light transmittance

Question 22

Describe effective bandwidth

Answer 22

• range of wavelengths at a point halfway between the baseline and the peak

Question 23

Describe Bandpass

Answer 23

• total range of wavelengths transmitted

Question 24

What types of filters are used in monochromators?

Answer 24

• absorption filter
• interference filters

Question 25

Describe prism monochromators

Answer 25

- types —> 60-degree —> 30-degree - depends on refraction of radiation by the prism material - dispersive power depends on the variation of the refractive index with wavelength - ray of radiation that enters prism at an angle of incidence is bent away from vertical - dispersed light appears the spectrum of colors that make up the incident radiation

Question 26

Describe grating monochromators

Answer 26

- the surface is characterized as an array of a very large number of slits spaced equidistant from each other that reflect or transmit radiation - only at certain definite angles is radiation of any given wavelength in phase, at others angles, the waves from the slits destructively interfere

Question 27

What does the quality of grating depend on?

Answer 27

1) straightness of the grooves 2) the degree of parallelism 3) the equidistant of the grooves to each other

Question 28

Describe cuvettes

Answer 28

- cell hold samples and reagents that are made of material transparent to radiation in the spectral region of interest - flow-cell or flow-through cuvette

Question 29

Describe radiation transducer

Answer 29

- a device that converts one form of energy to another —> photovoltaic or barrier layer cell —> vaccuum phototubes —> photo multiplier tubes —> silicon diode transducers —> multichannnel photon transducers —> photodiode arrays —> charge-transfer devices

Question 30

Describe signal processors and readout

Answer 30

- processing of an electrical signal received from a transducer is accomplished by a device that: 1. Amplifies the electronic signal 2. Rectifies alternating current (ac) to direct current (dc) or the reverse 3. Alters the phase of the signal 4. Filters it to remove unwanted components

Question 31

What photometric parameters should be monitored periodically to ensure optimal performance?

Answer 31

- wavelength accuracy - bandwidth - photometric accuracy - linearity - stray light

Question 32

What does accuracy suggest?

Answer 32

The closeness of a measurement to its true value

Question 33

What is used to assess photometric accuracy?

Answer 33

- glass filters or solutions that have known absorbance values for a specific wavelength

Question 34

What devices are used to determine linearity of the spectrophotometer?

Answer 34

- stray light - spectroscope - colorimeter - photometer - spectrometer - spectrophotometers - single-beam instrument

Question 35

Describe stray light

Answer 35

- can have a significant impact on any measurement of absorbance by a solution - can be evaluated by using special cutoff filters

Question 36

Describe spectroscope

Answer 36

- optical instrument used for visual identification of atomic emission lines

Question 37

Describe colorimeter

Answer 37

- user compares the observed color of the unknown sample to a standard or a series of colored standards of known concentrations

Question 38

Describe photometer

Answer 38

- consists of a light source, monochromatic filter and photoelectric transducer, signal processors and readout

Question 39

Describe spectrometer

Answer 39

- an instrument that provides information about intensity of radiation as a function of wavelength or frequency - single-beam instruments represents the simplest type of spectrometer

Question 40

Describe spectrophotometers

Answer 40

- spectrometers equipped with one or more exit slits and photoelectron transducers that permit determination of the ratio of the power of two beams as a function of wavelength

Question 41

Describe double-beam instrument

Answer 41

- splits or chops the monochromatic beam of radiation into two components - two fundamental —> double beam in space —> double beam in time

Question 42

Describe reflectometer

Answer 42

- a filter photometer that measures the quantity of light reflected by a liquid sample that has been dispensed onto a non polished surface

Question 43

What are 2 types of reflectance?

Answer 43

- specular reflectance - diffuse reflectance

Question 44

Describe specular reflectance

Answer 44

- occurs on a polished surface, where the angle of incidence of the radiant energy is equal to the angle of reflection

Question 45

Describe diffuse reflectance

Answer 45

- occurs on nonpolished surfaces - occurs within the layers and depends on the properties and characteristics of the layers themselves

Question 46

What are components of a reflectometer?

Answer 46

* similar to photometer - Tungten-quartz halide lamp serves as a source of polychromatic radiation - light passes through a slit and is directed onto the surface of a urine dipstick pad or dry slide - A wavelength selector, such as stationary filter or filter wheel for multiple analytes, is used to isolate the wavelength of interest - solid-state photodiode are typically used to detect the reflected radiant energy

Question 47

Describe the Atomic Absorption Spectroscopy (AAS)?

Answer 47

- used for quantitative analysis or metals such as calcium, lead, copper and lithium - time-consuming to perform, is labor intensive and requires meticulous laboratory techniques - measures the amount of EMR absorbed by elements in their ground state - amount of absorbed radiation is directly proportional to the concentration of of the metal in solution (G-degree)

Question 48

What is used for molecular luminescence spectroscopy?

Answer 48

Fluorometry

Question 49

Describe fluorometry

Answer 49

- fluorescent spectroscopy is widely used because of its inherent high sensitivity and high specificity - high specificity results from dependence on two spectra and the possibility of measuring the lifetimes of the fluorescent state (excitation and emission spectra) - compounds that are excited at the same wavelength but emit at different wavelengths are readily differentiated

Question 50

What is the principle of luminescence fluorometry?

Answer 50

- based on an energy exchange process that occurs when valence shell electrons absorb EMR, become excited, and return to an energy level lower than their original level

Question 51

What is the principle of fluorescence fluorometry?

Answer 51

Light emission from a singlet-excited state

Question 52

Describe principles of phosphorescence fluorometry

Answer 52

Light emission from an excited triplet state

Question 53

Describe instrumentation of fluorometry

Answer 53

- conventional design of fluorometers places the detector at a 90-degree angle to the polychromatic light source - sources: —> intensity —> wavelength distribution of emitted radiation stability - filters and monochromators - transducers - cuvettes or cells

Question 54

Describe transducers of fluorometry

Answer 54

- PMTs are the most common transducers found in fluorescent instruments - newer fluorometers on the market today use diode-array and CTDs

Question 55

Describe cuvette or cells of fluorometry

Answer 55

- used for fluoroscent measurement may be rectangular or cylindrical - may be made of glass or quartz

Question 56

Describe applications of fluorescent spectroscopy

Answer 56

- fluorescence polarization immunoassay - time-resolved fluorescent immunoassay - front-surface fluorometry - chemiluminescence

Question 57

Describe fluorescence polarization immunoassay

Answer 57

- measurement of fluoroscent-labeled bound fraction is determined in the presence of fluorescent- labeled free fraction - referred to as a homogenous immunoassay

Question 58

Describe chemiluminescence of fluorometry

Answer 58

- differs from fluorescence and phosphorescence - light is produced from a chemical or electrochemical reaction and not from electromagnetic energy stimulation of electrons, resulting in emission of photons

Question 59

What are light scatter techniques?

Answer 59

- nephelometry - turbidimetry

Question 60

Describe Nephelometry

Answer 60

- measurement of the light scattered by particles in solution - typical nephelometer consists of a light source, a collimator, a monochromator, sample cuvette, a stray light trap, and a photo-detector

Question 61

Describe turbidimetry

Answer 61

- measurement of the reduction in light transmission caused by particle formation - light transmitted in the forward direction is detected - the amount of light scattered by a suspension of particles depends on the specimen concentration and particle size

Question 62

What is the principle of refractometry

Answer 62

- based on the refraction of light as it passes through a medium such as glass or water - when light passes from one medium into another, the light bam changes its direction at the boundary surface if its speed in the second medium is different from that in the first - critical angle: the angle is created by the bending of the light - refractivity: the ability of substance to bend light

Question 63

Describe osmometry

Answer 63

- the measurement of the osmolarity of an aqueous solution such as serum, plasma, or urine

Question 64

What occurs as osmolarity of solution increases?

Answer 64

1. Osmotic pressure increases 2. Boiling point is elevated 3. Freezing point is depresssed 4. Vapor pressure is depressed

Question 65

Describe freezing-point osmometer

Answer 65

- consists of a sample chamber containing a stirrer and a thermistor connected to a readout device - sample is rapidly supercooled to several degrees below its freezing point - then agitated with the stirrer to initiate freezing - rate at which this heat of Fusion is released from the ice being rapidly formed reaches equilibrium with the rate of heat removed —> known freezing point of solution

Question 66

What is used in electrochemistry?

Answer 66

Potentiometry

Question 67

Describe potentiometry

Answer 67

- electrical potentials are produced at the interface between metal and ions of that metal in a solution - to measure the electrode potential, a constant-voltage source is needed as the reference potential —> reference electrode: electrode with a constant voltage —> indicator electrode: the measuring electrode

Question 68

Describe Nernst equation

Answer 68

- measured cell potential is related to the molar concentration by the Nernst equation - useful for predicting the elelctrochemical cell potential given the concentrations of oxidized and reduced species for a given electrode system

Question 69

What is the Nernst equation?

Answer 69

Ec = Eo - (RT/nF)lnQ Ec = cell potential Eo = cell potential under standard conditions R = Universal gas constant (8.314 J/(mol*K)) T = temperature - n = number of electrons transferred in the reaction F = Faraday constant (96485 C/mol) Q = Reaction quotient

Question 70

Describe reference selective electrodes of potentiometry

Answer 70

- in most electro analytical applications, it is desirable the half-cell potential of one electrode be known, constant, and completely insensitive to the composition of the solution under study

Question 71

What are important attributes of a reference selective electrode?

Answer 71

1. Potential is reversible and obeys the Nernst equation 2. Electrode exhibits a potential that is constant with time 3. Electrode returns to its original potential after being subjected to small currents 4. Electrode exhibits little hysterics or lag with temperature cycling

Question 72

Describe ion-selective electrode of potentiometry

Answer 72

- ISE is a membrane-based electrochemical transducer capable of responding to a specific ion. - ISEs measure ion activities, specifically free ion concentration - ISEs provide several advantages over “wet chemistry” and photometric techniques

Question 73

Describe pH electrodes of potentiometry

Answer 73

- consists of a small bulb located at the tip of the electrode made of layers of hydrated and non hydrated glass - inside the electrode is a chloride ion buffer solution

Question 74

Describe PCO2 electrodes of potentiometry

Answer 74

- a pH electrode contained within a plastic “jacket” - a plastic jacket is filled with a sodium bicarbonate buffer and has a gas-permeable membrane across its opening

Question 75

Describe coulometry

Answer 75

- an analytical method that involves measuring the quantity of electricity (in coulombs) needed to convert the analyte quantitatively to a different oxidation state

Question 76

What is a coulomb?

Answer 76

The quantity of electricity or charge that is transported in one second by a constant current of one ampere

Question 77

What are laboratory applications of coulometry?

Answer 77

- the measurement of chloride ions in serum, plasma< CSF and sweat samples

Question 78

Describe Amperometry

Answer 78

- measure meant of the current flow produced by an oxidation-reduction reaction

Question 79

What are the electrochemical methods used for measuring chloride in samples?

Answer 79

- coulometry - amperometry

Question 80

Describe chloride titrator of amperometry

Answer 80

- includes a pair of silver electrodes that serve as the indicator electrodes - when all of the chloride in the sample has been consumed, silver ions appear in excess

Question 81

Describe PO2 gas-sensing electrode of amperometry

Answer 81

- Clark PO2 electrode consists of a gas-permeable membrane, usually polypropylene, that allows dissolved oxygen to pass through

Question 82

Describe voltammetry

Answer 82

- comprises of a group of elelctroanalytical methods in which information about the analyte is derived from the measurement of current as a function of an applied potential under conditions that promote polarization of an indicator, or working electrode - based on the measurement of a current that develops in an electrochemical cell under conditions of complete concentration polarization - a minimal consumption of analyte takes places

Question 83

Descartes Anodic stripping voltammetry

Answer 83

- measurement of lead in whole blood samples can be performed in the clinical laboratories - Technique consists of three major steps: 1. Reduction of lead and deposition of the lead onto the electrode 2. “Resting period” in which stirring is halted but the potential remains on the electrode 3. Lead is stripped from the electrode back into the solution by oxidation to the iconic form

Question 84

Describe conductometry

Answer 84

- electrolytic conductivity is a measure of the ability of a solution to carry an electric current - The reciprocal of resistance, 1/R is called the conductance, given the symbol G, and is expressed in reciprocal ohms, or mhos

Question 85

Describe Resistivity

Answer 85

- the electrical resistance in ohms measured between opposite faces of a 1.00- centimeters cube of an aqueous solution at a specific temperature - measurement is accomplished by using a resistivity meter

Question 86

Describe Impedance

Answer 86

- electrical impedance measurement is based on the change in electrical resistance across an aperture when a particle in a conductive liquid passes through this aperture

Question 87

What are separation techniques?

Answer 87

- electrophoresis - densitometry - chromatography

Question 88

Describe electrophoresis

Answer 88

- separation of charged compounds, typically proteins, applied to a solid or semisolid support and immersed in a liquid medium - pH at which an amino acid exists mainly as the zwitterion is called the isoelectric point and the pH at that point is called the pI - conductivity of a solution increases with its total ionic concentration

Question 89

Describe densitometry

Answer 89

- basically an absorbance measurement

Question 90

Describe Densitometer

Answer 90

- measures the absorbance of the stained compounds on a support medium or electrophoretic strip - light source, monochromator, and movable carriage to move the electrophoretic strip between the monochromator and photodiode and a photodetector

Question 91

Describe capillary electrophoresis

Answer 91

- typical CE system consists of a fused silica capillary, two electrolyte buffer reservoirs, a high-voltage power supply, and a detector lined to a data acquisition unit

Question 92

What is electroosmosis?

Answer 92

Motion of a liquid when a voltage is applied between the ends of an insulating tube that contains that liquid

Question 93

Describe isoelectric focusing

Answer 93

- IEF techniques are similar to electrophoresis except that the separating molecules migrate through a pH gradient - pH gradient is created by adding acid to anodic area of the electrolyte cell and adding base to the cathode area - has been useful is measuring serum isoenzymes of acid phosphatase, creatine kinase, and alkaline phosphatase

Question 94

Describe retentions time (Rt) of chromatography

Answer 94

- time it take a compound to elite off the column once it has been injected - can be used to determine a compounds identify

Question 95

Describe resolution (Rs)

Answer 95

- measure of the ability of a column to separate two or more analytes in a sample

Question 96

What are factors that have a significant impact on the ability of chromatographic system to separate compounds?

Answer 96

- column retention factor (k’) - column efficiency (N) - column selectivity (alpha)

Question 97

Describe k’

Answer 97

- strength of solvent: polarity - strength of packing material: surface area or amount of stationary phase - temperature

Question 98

Describe N

Answer 98

- flow rate: linear velocity - column length - average particle of size of packing material - viscosity of solvent - mass of injection

Question 99

Describe alpha

Answer 99

- chemistry of solvent: functional groups - chemistry of packing material: functional groups - chemistry of samples: presence of hydrogen bonds or derivatization

Question 100

Describe Thin-layer chromatography

Answer 100

- used in many laboratories as an initial screening technique for the detection of drugs of abuse in urine (DAU) - stationary phase is manufactured as a thin layer or coating of absorbent that is bonded to a solid support such as glass or plastic —> solid absorbent may consist of a basic silica material or a more complex absorbent - most compounds have a characteristics identifier known as R1

Question 101

Describe gas chromatography (GC)

Answer 101

- uses a “carrier” gas to move compounds through a stationary phase located within column - widely used technique for decades because of: —> high resolution —> low detection limits —> accuracy —> short analytical times

Question 102

Describe the basic design components of GC

Answer 102

- carrier gas supply - sample injection device and GC inlet - column - detector - data system

Question 103

Describe liquid chromatography (high performance liquid chromatography

Answer 103

- techniques use lower temperature for separation , thereby achieving better separation of thermolabile compounds - uses small, rigid supports and special mechanical pumps producing high pressure to pas the mobile phase through the column - five commonly used separation techniques: —> adsorption —> partition —> ion exchange —> affinity —> size exclusion

Question 104

What does the HPLC instrumentation consists of?

Answer 104

- liquid mobile phase - sample injector (manual or automatic) - mechanical pump - column - detector - data recorder

Question 105

What are the two methods for delivery of mobile phases of HPLC instrumentation?

Answer 105

1. Isocratic : used one mobile phase 2. Gradient: involves the use of two or more mobile phases that are automatically programmed to pump for a specific interval of time

Question 106

Describe Mass spectroscopy

Answer 106

- used to identify unknown compounds, determine concentrations of known substances the molecular structure and chemical composition of organic and inorganic material

Question 107

What are the steps of Mass spectroscopy?

Answer 107

1. Atomization 2. Conversion of a substantial fraction of atoms formed in step 1 to a stream of ions 3. Separation of the ions formed in the second step on the basis of their mass-to-charge ratio (m/z) —> m is the mass of the ion is atomic mass units and z is its charge 4. Counting the number of ions of each type or measuring current produced when the ions formed from the samples strike a transducer

Question 108

Describe mass-to-charge ratio

Answer 108

- measurement commonly used in MS - obtained by dividing the atomic or molecular mass of an ion by the number of charges that ion bears - often shortened to the more convenient term mass

Question 109

What are the 3 components of mass spectrometers?

Answer 109

- ion source 1. Electrospray ionization (ESI) 2. Matrix-associated laser desorption ionization (MALDI) 3. Surface-enhanced laser desorption ionization (SELDI) - mass analyzer - ion detector

Question 110

What are the 5 types of mass analyzers?

Answer 110

1. ESI-QqQ (triple quadrupole) 2. ESI-QIT (quadrupole ion trap) 3. MALDI-ToF-MS (time of flight) 4. ESI-QqToF (quadrupole time of flight) 5. ESI-FTMS (Fourier transforms)

Question 111

Describe time of flight of mass analyzers

Answer 111

- consists of a metal flight tube - m/z ratios of the ions are determined by accurately and precisely measuring the time it takes ions to travel from the MALDI or SELDI sources to the detector

Question 112

Describe scintillation counters

Answer 112

- an instrument that detects scintillations using a PMT and counts the electrical impulses produced by the scintillations - chemical used to convert their energy into light energy are called scintillators - PMT detects light either directly or through an internal reflecting fiber optic

Question 113

What are scintillations?

Answer 113

- are flashes of light that occur when gamma rays or charged particles interact with matter

Question 114

What are the two types of scintillations methods that exists?

Answer 114

- crystal scintillations - liquid scintillations

Question 115

Describ crystal scintillations counters

Answer 115

- used to detect scintillations created by interaction of gamma particles from radioisotopes with matter

Question 116

Describe liquid scintillations counters

Answer 116

- sued to detect and count photons that are produced when beta radiation from radioisotopes interacts with matter

Question 117

Describe Nuclear magnetic resonance (NMR)

Answer 117

- occurs when the nuclei of certain atoms are immersed in a static magnetic field and exposed to a second oscillating magnetic field, the magnetic component of EMR

Question 118

What are the basic components of NMR spectrometer?

Answer 118

- magnet used to separate the nuclear spin energy state - transmitter that supplies the radio frequencies (RFs) or irradiating energy - sample probe - computer

Question 119

Describe the flow cytometer

Answer 119

- instrument that measures multiple cell parameters and other types of particles as they flow individually in front of light source

Question 120

What are key features of a flow cytometer

Answer 120

- cells or particles - illumination - fluidics - detector - data

Question 121

Describe illumination of flow cytometry

Answer 121

- laser light —> serves as a source of illumination for most flow cytometer —< provides intense light in a narrow beam

Question 122

Describe fluidics of flow cytometry

Answer 122

- the particles need to be suspended in a fluid —> decreased the probability that multiple cells will group together at the analysis point

Question 123

Describe the detector of flow cytometry

Answer 123

- lenses are used to collect the light and focus the beam of radiation onto a photodiode - only light the has been refracted or scattered as it strikes will be diverted enough to strike the forward-positioned lens and the photodiode behind it

Question 124

Describe data of flow cytometry

Answer 124

- all data about each of a group of cell is stored in data files in an array where each cell has the associated output from each detector - software packages available will produce histograms and scatter grams of any set of parameter values for the cells in the data file

Question 125

What are some types of microscale technologies?

Answer 125

- lab-on-a-chip - micro machining - outdoes - biosensors

Question 126

Describe Lab-on-a-Chip of microscale technologies

Answer 126

- a total microanalysis system (uTAS) incorporating sample preparation, separation, detection, and quantification on a microchip surface

Question 127

Describe micro machining of microscale technologies

Answer 127

Process of fabricating labs-on-a-chip and micro machines

Question 128

Describe optodes of microscale technologies

Answer 128

- optical sensors - used in clinical laboratory instrumentation designed to measure blood gases and electrolytes

Question 129

Describe Biosensors

Answer 129

- a device with a biologically sensitive coating comprising an antibody, receptor protein or biocatalysts - comprises a biologically sensitive material (a biocatalyst) in contact with a suitable transducing system that converts the biochemical signal into an electrical signal

Question 130

What are biocatalyss of biosensors?

Answer 130

- enzyme - multienzyme systems - antibodies - membrane components - organelles - bacteria - mammalian or plant tissues

Question 131

What are biocatalysts responsible for?

Answer 131

- for the sensitivity and specificity of the biosensors

Question 132

What are the types of biosensors used in the laboratories?

Answer 132

- electrochemical - conductimetric - piezoelectric - calorimetric - optical

Question 133

What are the respective transducer systems for electrochemical microscale technologies?

Answer 133

- potentiometric - amperometric

Question 134

What is the respective transducer system for piezoelectric?

Answer 134

- applied using crystals of quartz coated with an adsorbent

Question 135

What is the respective transducer for calorimetric?

Answer 135

- biological component attach to a heat-sensing transducer or thermistor - reaction between these two components generates a specific amount of heat

Question 136

What is the respective transducer of optical of microscale technologies?

Answer 136

- uses fiber-optic technology to measure the reflected fluorescence light from immobilized chemicals at the ed of small fiber-optic probes

Question 137

Describe enzyme based biosensors with amperometric detection of microscale technologies

Answer 137

- development of electrodes to measure cholesterol, pyruvate, alanine, and creatinine

Question 138

Describe enzyme-based biosensors with potentiometric and conductometric detection of microscale technologies

Answer 138

- developed for the measurement of BUN, glucose, creatinine and acetaminophen

Question 139

Describe enzyme-based biosensors with optical detection of microscale technologies

Answer 139

- used to measure analytes such as glucose, cholesterol and bilirubin

Question 140

Describe affinity biosensors of microscale technologies

Answer 140

- use binding proteins, antibodies, or oligonucleotide as an immobilized biological recognition element

Question 141

Describe Point of Care (POC) of biosensor technologies

Answer 141

- any test that is performed at the time at which the test result enables a decision to be made and an action taken that leads to an improved health outcome - devices are designed to provide both qualitative and quantitative measurements - strips - sensors - devices should: —> be portable —> have consumable reagent cartiridges —> generate results within minutes —> require minimum operating steps —> have the capability to perform tests on whole blood specimens —> have flexible test menus —> contain built-in/integrated calibration and quality control —> require ambient temperature storage for reagents

Question 142

What analytes are measured with reflectance?

Answer 142

- urine and blood chemistries

Question 143

What analyte is measure with lateral-flow immunoassay?

Answer 143

- infectious disease agents, cardiac markers, human chorionic gonadotropin

Question 144

What analyte is measured with electrochemistry?

Answer 144

- glucose, pH, blood gases, electrolytes, metabolites

Question 145

What is analyte is measured by light scattering?

Answer 145

- coagulation

Question 146

What analyte is measured by immunoturbdity?

Answer 146

HbA1c, urine albumin

Question 147

What analyte is measured by spectrophotometry?

Answer 147

- blood chemistry

Question 148

What analyte is measured by fluorescence?

Answer 148

- pH, blood gases, electrolytes, metabolites

Question 149

What analyte is measured by multi wavelength spectrophotometers?

Answer 149

Hemoglobin species, bilirubin

Question 150

What analyte is measured by electric impedance

Answer 150

- complete blood count

Question 151

What analyte is measured by time-resolved fluorescence?

Answer 151

- cardiac markers, drugs, C-reactive protein

Question 152

Describe laboratory automation

Answer 152

- main impetus behind automation has been needed to create automated systems capable of reducing or eliminating the manual tasks required to perform analytical procedures - use of LIS was a decrease in the expected 5% transcription error rate seen when laboratory results were manually transcribed

Question 153

What are laboratory demands that drive automation?

Answer 153

- reduction in turnaround time (TAT) - medical laboratory staff shortages - economic factors - less maintenance - less down time - 24/7 uptime - increaesed throughout - computer and software technology - primary tube sampling - increased number of different analytes on one system - increased number of different methods on one system, - reduced lab errors - increaesed in number of specimens - improved safety of CLS - environmental concerns such as biohazards risks

Question 154

What are advantages of automating chemical analysis?

Answer 154

- reduced errors - reduced cost - staff free to run additional tests - reduced imprecision - reduced TATs - reduced safety-risk factors - reduced repetitive- stress injuries - consistent sample processing

Question 155

What is specimen throughput of automated analysis?

Answer 155

- number of tests performed per hour

Question 156

What is discrete testing of automated analysis?

Answer 156

- measures only the test requested on a sample

Question 157

What is Batch analysis of automated analysis?

Answer 157

- a group of samples is prepared for analysis - a single test is performed on each sample in the group

Question 158

What is Random-access testing of automated analysis?

Answer 158

- measure any specimen by a common to the processing systems - analyze the specimen by any available process —> in or out of sequence with other specimens —> without regard to their initial order

Question 159

Describe preanalytical stage

Answer 159

- involves primarily sample or specimen processing - methods to transport specimens —> human carriers or runners —> pneumatic-tube delivery systems —> electric-track-driven vehicles —> mobile robots —> conveyors or track systems

Question 160

What are some examples of sample-processing tasks?

Answer 160

- identify specimens - label specimens using bar-code lables - sort and route - centrifuge sample tubes - decap tubes - prepare sample aliquots - recap, store, retrieve - transport - detect sample level - store and retrieve

Question 161

Describe automated specimen processing of preanalytical stage

Answer 161

- also known as front-end sample processing - represents the most cost-effective automaton strategies for the clinical laboratory

Question 162

What are two goals of automated specimen processing of preanalytical stage?

Answer 162

1. Minimize non-value-added steps in the laboratory process 2. Increase available time for value-added steps in the tasks that the CLS performs

Question 163

What are some specimen handling tasks that can be performed with integrated specimen processing?

Answer 163

- presorting - centrifugation - volume checks - clot decision - decapping - secondary tube labeling - aliquoting - destination sorting into analyzer racks

Question 164

Describe sample introduction for the analytical stage

Answer 164

- automation sampling may be accomplished using several different physical mechanisms - in most, analyzers, samples are transferred using a thin, stainless steel probe. - another feature associated with sampling is the ability of the sampler to detect the presence of a liquid -

Question 165

What is liquid level sensor?

Answer 165

- designed to detect the presence of a sample by measuring the electrical capacitance of the surrounding area

Question 166

What are some tasks included in the analytical stage of laboratory testing?

Answer 166

- sample introduction and transport to cuvette or dilution cup - reagent measurements, transport, and introduction to cuvette - mixing of sample and reagent - incubation - detection - calculations - readout and result reporting

Question 167

Describe reagents of the analytical stage

Answer 167

- most laboratories use bulk reagents - chemistry analyzers that use unit test reagents may require some preparation - complete inventory is established on a real-time basis within the computer - on-board reagent storage compartments are refrigerated to maintain reagent stability - correct proportions important for accuracy and precision - liquid reagents are aspirated, delivered, and dispensed by pumps or positive- displacement syringes - direct tube sampling is offered on new model lines

Question 168

What are automated analyzers categorized as?

Answer 168

Open or closed

Question 169

Describe open-reagent analyzer

Answer 169

- reagents other than the manufactures reagents can be used

Question 170

Describe closed-reagent analyzer

Answer 170

- operator can only use the instrument manufactures reagents

Question 171

How do instruments perform mixing?

Answer 171

- magnetic stirring - rotating paddles - forceful dispensing - use of ultrasonic energy - vigorous lateral displacement

Question 172

Describe incubation of the analytical stage

Answer 172

- warming of instrument components or solution in automated analyzers - must be constant and accurate - timing is monitored by the instruments computer system —> represents an extremely complex process given the throughout for these systems

Question 173

Describe detection of the analytical stage

Answer 173

- in automated analyzers, absorption spectroscopy remains the principal means of measuring a wide variety of compounds - electrochemiluminescent methods have also been incorporated.

Question 174

How do instruments perform incubation?

Answer 174

- circulating water baths - peltier-thermoelectric module

Question 175

How do instruments perform detection?

Answer 175

- photometer/spectrophotometer - fluorimeters - electrochemical - luminometer - infrared detectors

Question 176

Describe signal processing of postanalytical stage

Answer 176

- involves conversion of an analog signal derived from the detector to a digital signal usable by all communication devices

Question 177

What does data processing by computers include?

Answer 177

- data acquisition - calculations - monitoring and displaying data

Question 178

Describe computers of postanalytical stage

Answer 178

- have profoundly affected the entire process of automated laboratory instruments - provide a means of communication between the analyzer and operator - have the ability to be linker to other computers —> has drastically improved automation efforts - many have on-board trouble shooting capabilities

Question 179

Describe total laboratory automation (TLA)

Answer 179

- refers to combination of pre-analytical, intra-analytical and post-analytical components interconnected together

Question 180

What are advantages of TLA ?

Answer 180

- decrease in labeling errors - reduced turnaround times - potential reduction in full-time equivalents (FTEs)

Question 181

What are disadvantages of TLA?

Answer 181

- needs for substantial financial investment - increased floor space

Question 182

Describe integrated modular system

Answer 182

- provide a more attractive approach for hospital laboratories and physician group laboratories because the systems are smaller, require less initial capital investment, and require less planning

Question 183

Describe workstations

Answer 183

- represents a unique environment within a laboratory facility dedicated to one type of testing

Question 184

Describe work cells

Answer 184

- combination of a specimen manger with instruments or consolidated instruments of chemistry and immunoassay reagents - provide a broad spectrum of analytical tests - specimen manger - modular work cells

Question 185

Describe fully integrated systems

Answer 185

- trend to integrate several modules into one continuous system that will allow the used to assay photometric, immunoassay and electrochemical assays - use random-access technology to allow the analysis of several types of chemistry assays

Question 186

What are the options of integrated automated systems?

Answer 186

- instrument connectors - middleware

Question 187

Describe instrument connectors

Answer 187

- AU-connector uses intelligent sample management and tube-presorting capabilities —> keeps all the analyzes working at full potential

Question 188

Describe middleware

Answer 188

Software that allows a laboratory to: - connect its existing LIS and instrumentation to facilitate automating information - perform tasks not currently done with the laboratory’s existing hardware and software

Question 189

What are some future trends?

Answer 189

- test menus will continue to increase - multiple detectors and platforms will be incorporated into a single automated system —> provide users with more flexibility - increased interest in proteomics will eventually bring this discipline into the clinical laboratory

Question 190

Describe laboratory information systems (LIS)

Answer 190

- described as a group of microprocessors and computers connected together to provide management and processing of information - span all three phases of testing

Question 191

What are some patient demographics?

Answer 191

- patient name - sex - age/DOB - patient number (assigned by health-care facility) - referring physician - admitting diagnosis

Question 192

What items are in order entry?

Answer 192

- patient identifiers - ordering physician - test-request time and date - test name - test priority - special instructions pertaining to the request - specimen draw time

Question 193

Describe protein

Answer 193

- complex polymers of alpha-amino acids that are produced by living cells in all forms of life - each protein is composed of a maximum of 20 different amino acids in varying numbers and sequences

Question 194

What do proteins contain?

Answer 194

- carbon - hydrogen - oxygen - nitrogen - some include sulfur

Question 195

What does amino acids contain?

Answer 195

- amino group (NH2) - carboxyl group (COOH) - hydrogen - R group with formula RCH(NH2)COOH

Question 196

Describe protein structure

Answer 196

- structure of amino acids is amphotetic-containing two ionizable sites, a photon-accepting group (NH2) and a proton-donating group (COOH) - when both are ionized, the amino acid is called an ampholyte or depolar ion

Question 197

Describe isoelectric point (pI)?

Answer 197

- the pH at which when amino acid or protein has no net charge and the positive charges equal the negative charges - At a pH greater that the pi, the protein carries a negative charge and at a pH less than the pi, the protein carries a positive charge

Question 198

Describe peptide bonds of protein structure

Answer 198

- a molecule of water is split between the carbonyl group of one amino acid and the amino group of another and a covalent bond called a peptide bond - the end of the protein that has the amino-free group, is called the N-terminal end - the opposite end has the carboxyl-free group, is called the C-terminal end.

Question 199

Describe primary structure

Answer 199

- the sequence of amino acids in the polypeptide chain-the identity and specific order of the amino acids

Question 200

Describe secondary structure

Answer 200

- determined by the interaction of adjacent amino acids - three-possible conformations are the alpha-helix, beta-pleated sheets, and random coils

Question 201

Describe tertiary structure

Answer 201

- the way in which the chain folds back upon itself to form a 3D structure - these are mainly interactions of amino acids with the R-groups of more distant amino acids - determines the chemical and physical properties of the protein

Question 202

Describe the quaternary structure

Answer 202

- the arrangement of two or more polypeptide chains to form a protein - only proteins with more than one polypeptide chain have this,

Question 203

Describe denaturation

Answer 203

- disruption of the bonds holding the secondary, tertiary, or quaternary structures together - can occur as a result of heat, changes in pH, mechanical forces, exposure to chemicals (solvents, detergents, metals) and exposure to ultraviolet light

Question 204

Describe protein metabolism

Answer 204

- digestion of dietary proteins by proteolytic enzymes —> originates in the GI tract - liver and other organs utilize the amino acid pools to synthesize the body’s protein

Question 205

Where are amino acids filtered in through the kidneys?

Answer 205

- renal glomeruli —> subsequently reabsorbed by the renal tubules

Question 206

Describe protein synthesis

Answer 206

- most plasma proteins are synthesized in the liver and secreted into circulation by the hepatocytes - double-stranded DNA molecule unfolds —> one strand serves as a template for the messenger RNA (mRNA) - code is carried by the mRNA from nucleus to cytoplasm —> attaches to a ribosome receptor protein - amino acid linked to transfer (tRNA) that corresponds to the specific codon is carried to the ribosome ad is attached to the matching codon - Next amino acid in the sequence is added - cycle repeats itself until the protein is completed

Question 207

What are the BASIC functions of proteins?

Answer 207

- maintenance of water distribution between cells and tissue —> when protein levels are decreased, the osmotic pressure is also decreased - coagulation proteins are important in maintenance of hemostasis - many proteins function as transport vehicles to move various ligands to where they are needed or stored - structural support (collagen, Keratin) - enzymes - peptide hormones, insulin - hemoglobin - antibodies

Question 208

What are examples of tranport molecules (proteins)?

Answer 208

- transferrin- Fe+3 - Albumin-bilirubin - thyroid binding globulins - hormones

Question 209

Describe Aminoacidopathies

Answer 209

- inherited disorders of amino acid metabolism

Question 210

What are some aminoacidopathies?

Answer 210

- alkaptonuria - cystinuria - maple syrup urine disease - phenylketonuria

Question 211

Describe Alkaptonuria

Answer 211

- rare inherited disease involving the homogentistic acid oxidase (HGO) - leads to a buildup of homogetistic acid (HGA) in the tissues of the body - autosomal recessive condition - ochronotic

Question 212

What is Ochronotic?

Answer 212

- darkening of the tissues of the body because of excess homogentisic acid

Question 213

Describe the cystinuria

Answer 213

- defect in the amino acid transport system - is somewhat insoluble, which results in precipitation in the renal tubules, formation of urinary calculi

Question 214

Describe Maple Syrup Disease

Answer 214

- named for characteristics maple syrup or burnt sugar odor of the urine - caused by the absence or very low levels of the branched-chain enzyme alpha-ketoacid decarboxylase comple —> results in abnormal metabolism of 3 essential amino acids: leucine, isoleucine, and valine - treatment involves a special, very controlled diet required careful monitoring of protein intake

Question 215

Describe Phenylketonuria

Answer 215

- inborn error of metabolism —> results in the inability to metabolize the essential amino acid phenylalanine - autosomal recessive trait - pregnant women known to be carriers of PKU gene or definitely carrying a PKU fetus should also be maintained on a phenylalanine-restricted diet from conception to birth - elevated phenylalanine levels are toxic to developing brain tissue and negatively impact brain function

Question 216

What are the 2 main group of proteins?

Answer 216

1. Albumin 2. Globulin

Question 217

What are the 4 types of globulins?

Answer 217

1. Alpha1-globulins 2. Alpha2-globulins 3. Beta- globulins 4. Y-globulins

Question 218

Describe prealbumin/transthyretin

Answer 218

- TTR binds with thyroxine and triiodothyronine (thyroid hormones) and retinol (vitamin A)

Question 219

What is the main clinical significance of prealbumin?

Answer 219

- role as a sensitive marker of poor nutritional status such as protein-energy malnutrition (PEM)

Question 220

Describe decreased prealbumin

Answer 220

- indicates dietary intake of protein is not adequate - results in decreased synthesis for prealbumin by the liver.

Question 221

What disorders are related to decreased albumin?

Answer 221

- acute inflammatory response (acute phase reactant, APR) - liver disease - Nephrotic syndrome - other protein- losing renal diseases

Question 222

Describe albumin

Answer 222

- synthesized in the liver - comprises approximately 60% of total serum protein - chief biological function is to maintain plasma colloidal osmotic pressure (COP) - another function is to transport and store a wide variety of ligands

Question 223

Describe hypoalbuminemia

Answer 223

- decreased albumin levels - most common cause is increased catabolism due to tissue damage and inflammation - impaired or decreased synthesis - increased loss of protein

Question 224

Describe hyperalbuminemia

Answer 224

- little diagnostic significance except in dehydration - increase is usually artifactual due to a decrease in plasma volume

Question 225

What are functions of albumin?

Answer 225

** Maintain plasma colloidal osmotic pressure - bind and transport a wife variety of ligands - serve as an endogenous source of of amino acid - acid base balance - pro- and anti-coagulatory effects

Question 226

What are the disorders associated with increased loss of protein?

Answer 226

- Nephrotic syndrome - Chronic glomerulonephritis - Diabetes mellitus/diabetic nephropathy - acute viral gastroenteritis

Question 227

Describe antitrypsin a1 (AAT)

Answer 227

- Antitrypsin a1 (AAT) is the major a1-globulin, makes up 90% of a1- proteins - it is an acute phase reactant (APR) with antiprotease activity resulting in the neutralization of leukocyte elastase and collagenase - AAT deficiency is one of the most common genetically lethal disease is Caucasians (1:4000)

Question 228

What disorders are associated with AAT deficiency?

Answer 228

- emphysema in absence of smoking - juvenile hepatic cirrhosis —> AAT is synthesized by the hepatocytes but not released

Question 229

Describe a1-glycoprotein (Orosomucoid)

Answer 229

- AAG is the major glycoprotein increased during inflammation, an APR - Elevated level are found in RA, cancer, pneumonia, and other conditions resulting in an APR

Question 230

Describe alpha-fetoprotein (AFP)

Answer 230

- a1 globulin - principle fetal protein (albumin-like protein) in maternal serum - used to screen for the antenatal diagnosis of neural tube defects including spina bifida and anencephaly - can be used as tumor marker

Question 231

What is AFP decreased in?

Answer 231

- Down’s syndrome - trisomy 18

Question 232

Describe haptoglobin (Hp)

Answer 232

- a2- globulins - an acute phase reactant that binds free hemoglobin in plasma - prevents loss of hemoglobin and its iron through the renal glomeruli - another role is control of local inflammatory response through a number of processes - APR that is synthesized late and is weak reacting

Question 233

What is the most sensitive indicator of intrvascular hemolysis, in transfusion reactions, and certian hemolytic disorders?

Answer 233

Depletion

Question 234

What conditions is haptoglobin increased in?

Answer 234

- inflammation - infection - tissue necrosis - malignancy

Question 235

Describe ceruloplasmin (Cp)

Answer 235

- a2-globulins - principal copper (Cu)-containing protein in plasma containing 95% of the total serum copper. Copper is very toxic to cells in high concentrations

Question 236

Where is the primary storage site of ceruloplasmin?

Answer 236

- liver

Question 237

Where is the principal site of excretions of ceruloplasmin?

Answer 237

Biliary tract

Question 238

Describe Wilson’s disease

Answer 238

- rare autosomal recessive trait where Cp levels are reduced and the dialyzable Cu concentration is increased - Cp is an APR that increases late in the condition

Question 239

What can excessive accumulations of Cu in the liver, kidney, and brain lead to?

Answer 239

- degenerative cirrhosis - chronic active hepatitis - renal tubular acidosis - Neuorlogical damage (clumsiness, tremors)

Question 240

What does Cu deposits in the eyes lead?

Answer 240

- results in characteristic Kaiser-Fleischer rings, pigmented rings at the outer margin

Question 241

Describe a2-macroglobulin (AMG)

Answer 241

- one of the largest plasma proteins - in nephrotic syndrome, AMG is increased up to 10 times normal because it is retained while smaller proteins are excreted in the urine - elevated in liver disease and estrogen —> slightly increased in diabetes mellitus

Question 242

Describe transferrin (TRF)

Answer 242

- major component of Beta-globulins - principal plasma protein for transport of iron (Fe+3 - ferric ion) to storage sites, whee it is bound to apoferritin and stored as ferritin - a negative APR

Question 243

What is important in differential diagnosis of anemias and monitoring the treatment of iron deficiency anemia?

Answer 243

Beta-globulin

Question 244

What is commonly used indicator of iron overload-screen for hemochromatosis?

Answer 244

Beta-globulins

Question 245

Describe hemopexin

Answer 245

- beta- globulins - removes heme from circulation - when RBC are destroyed, hemopexin transports heme to the liver, where it is catabolized by the reticuloendothelial system - increased level are found in pregnancy and in diabetes mellitus

Question 246

Describe Beta-lipoprotein

Answer 246

- Beta- globulins - classified as low-density lipoproteins (LDLs) —> transport the majority of cholesterol in the body from the liver to the tissues - high levels of LDLs are a risk factor atherosclerosis and heart disease

Question 247

Describe Beta2-microglobulin (BMG)

Answer 247

- low molecular weight protein - comprises the common light chain of class I MHC antigens found in all nucleated cells

Question 248

What is increased BMG associated with?

Answer 248

- renal failure - inflammation - neoplasms, especially the ones associated with B-lymphocytes

Question 249

Describe C- reactive protien (CRP)

Answer 249

- beta-globulin - an APR and a non specific indicator of bacterial or viral infection, inflammation and tissue injury or necrosis - reacts with proteins present in many bacteria, fungi and protozoal parasites - one of the first APRs discovered and one of the most sensitive

Question 250

When does CRP levels rise dramatically?

Answer 250

Following: - myocardial infarction - trauma - psychological or physical stress - infection - inflammation - surgery - various cancers

Question 251

What is valuable in diagnosing bacterial infections and in differentiating between bacterial and viral infections?

Answer 251

CRP

Question 252

Describe Y-globulin (gamma)

Answer 252

- immunoglobulins or humoral antibodies - each immunoglobulin (Ig) molecule consists of two or more basic units consisting of two identical heavy (H) chains and two identical light chains (L)

Question 253

Describe IgM

Answer 253

- largest Ig with a molecular weight of 900,000 for 5-10% of total Igs - first produced during in an immune response - primary response

Question 254

Describe IgG

Answer 254

- has a molecular weight of 150,000 - most abundant Ig in serum (70–75%) - IgG antibodies are produced in response to the antigens of most bacteria and viruses

Question 255

Describe IgA

Answer 255

- has a molecular weight of 160,000 - comprises 10-15% of Ig - secretory IgA, a dimer, is found in secretions including tears, sweat, saliva, and milk s well as GI and bronchial secretions

Question 256

Describe IgD

Answer 256

- molecular weight of 184,000 - makes up 61% of serum Igs - primary function is unknown

Question 257

Describe IgE

Answer 257

- has molecular wight of 180,000 - concentrations are very low (0.3 ug/mg) - produced in allergic reactions, urticaria, hay fever, and asthma

Question 258

Describe hyperproteinemia

Answer 258

- associated with a positive nitrogen balance — dietary nitrogen intake is greater than the excretion or loss of nitrogen, which occurs mainly in the urine —> usually occurs as a result of hemoconcentration or dehydration

Question 259

Describe Hypoproteinemia

Answer 259

- causes a negative nitrogen balance —> excretion of nitrogen exceed intake or synthesis of protein - most common cause is an increase in plasma water volume, or hemodilution - relative hypoproteinemia

Question 260

What are some causes of hypoproteinemia?

Answer 260

- increase increase in plasma water volume (hemodilution) - water intoxication - salt-retention syndromes - massive IV infusions - volume expanders - increase in protein loss (kidneys, GI tract, and skin) - Nephrotic syndrome - blood loss after trauma - burn patients - trauma - decreased synthesis - liver disease - immunodeficiency disorders

Question 261

What are some total protein methodologies?

Answer 261

- biuret - refractometry - dye-binding method - reference range

Question 262

Describe Biuret

Answer 262

- based on presence of peptide bonds found in all proteins - when a solution of protein is treated with Cupric (Cu+2) divalent ions in a moderately alkaline medium, a violet-colored chelate, which absorbs light at 540 nm, is formed between the cupric ion and carbonyl oxygen and the amide nitrogen atoms of the peptide bond

Question 263

Describe the biuret reagent

Answer 263

- sodium potassium tartrate —> complexed with cupric ions to prevent their precipitation in alkaline solution - copper sulfate: major reactant providing the Cu+2 ions - potassium iodide: antioxidant that stabalizes the cupric ions - NaOH: provides the alkaline pH

Question 264

Describe refractometry of total protein

Answer 264

- used for rapid, approximate measure of total serum protein concentration within the range of 3.5-10 g/dL - in plasma, the major solute protein is diluted in water and the refractive index of the solution increases in proportion to the concentration of the solute protein

Question 265

Describe Dye-binding method

Answer 265

- Coomassie Blue G-250, is dissolved in an acidic solution, causing it to absorb at 465 nm - the dye, which is negatively charged, binds to the positively charged protein molecule, the absorbance undergoes a shift to 595 nm —> used to determine the protein concentration

Question 266

Describe references range

Answer 266

- the serum protein in healthy, ambulatory adults in 6.0-8.3 g/dL - a physiological decrease of approximately 0.5 g/dL occurs in bed-ridden patients

Question 267

Describe A/G ratio

Answer 267

- globulin concentration can be calculated by subtracting the albumin from total protein - the A/G ratio can then be determined by dividing the albumin concentration by the calculated globulin

Question 268

What is the equation of A/G ratio?

Answer 268

Globulin = total protein (g/dL) - albumin (g/dL)

Question 269

Describe urinary proteins

Answer 269

- originate mostly form the blood and filtration through the renal glomeruli - proteins in the urine have been filtered by the glomeruli and have not been reabsorbed by the renal tubules

Question 270

What is the most common method of screening for urinary protein?

Answer 270

- urine reagent test strips —> indicator tetrabromphenol blue, at a pH of 3.0, is yellow in the absence of protein —> turns green and finally blue as the concentration of protein increases

Question 271

Describe cerebrospinal fluid protein

Answer 271

- CSF is a clear, colorless fluid that contains small amounts of glucose and protein - reference range is 15-45 mg/dL

Question 272

What are increased levels of CSF proteins associated with?

Answer 272

- various types of meningitis - encephalitis - subarachnoid hemorrhage - multiple sclerosis - Gillian-Barre syndrome - brain abscesses

Question 273

Describe albumin methodologies

Answer 273

- based on binding of albumin with anionic dyes —> Bromcresol green (BCG) — Bromsresol purple (BCP) - reference range for albumin 3.4-5.g/dL or 34-50 g/dL

Question 274

What are the 4 requirements of dye binding methods of albumin?

Answer 274

1. Specific binding of the dye to albumin in the presence of serum or plasma proteins 2. High binding affinity between the dye and albumin 3. Substantial shift in the absorption wavelength of the dye in the bound form 4. Absorption maximum for the bound form at a wavelength distinct from those where bilirubin and hemoglobin, the main interfering chromogens, can interfere

Question 275

Describe protein electrophoresis

Answer 275

- migration of charged solutes or particles in a liquid medium under the influence of an electrical field - proteins are ampholytes or zwitterions and can move toward the anode or cathode, depending on the Charge - performed on serum to avoid complication of the fibrinogen band in the beta-gamma region - after electrophoresis, the bands are fixed by immersing the strip in an acid medium

Question 276

Describe a normal serum protein electrophoresis (SPE)

Answer 276

- has five bands - % distribution X total protein = g/dL

Question 277

Describe fusion of B-Y bands or bridging

Answer 277

- results of fast-moving Y-globulins that prevent resolution of B- and Y-globulins

Question 278

What is the most common cause of B-Y bridging?

Answer 278

- cirrhosis —> can also be found in chronic infections and autoimmune or collagen disorders

Question 279

Describe nephrotic syndrome and abnormal protein electrophoresis

Answer 279

- characterized by a decrease in albumin and Y-globulin bands in conjunction with an increase in a2-globulins that suggest selective proteinuria

Question 280

Describe APR and abnormal protein electrophoresis

Answer 280

- APR that increase during APR are positive acute phase proteins (AAPs) - negative AAPs are albumin, transferrin, and transthyretin (prealbumin)

Question 281

What conditions are associated with increased APR?

Answer 281

- infection - tumor growth or malignancy - RA - Hepatitis - Surgery - trauma - burn - myocardial infarction

Question 282

Describe multiple myeloma

Answer 282

- cancer of the plasma cells - plasma cells produce immunoglobulins that normally protect us from infection but in multiple myeloma these are nonfunctional and are called paraproteins - increased in the Y globulin

Question 283

What is the first band of protein electrophoresis?

Answer 283

Albumin

Question 284

What is the second band of protein electrophoresis called and what does it consist of?

Answer 284

Alpha(1) —> a1 anti-trypsin —> a1 acid glycoprotein

Question 285

What is the third band of protein electrophoresis and what does it consist of?

Answer 285

- Alpha(2) —> a2-macroglobulin —> haptoglonulin

Question 286

What is the fourth band of protein electrophoresis and what does it consist of?

Answer 286

Beta - Hemopexin - transferrin - beta-lipoprotein - complement C3

Question 287

What is the fifth band of protein electrophoresis and does it consist of?

Answer 287

- gamma —> IgA —> IgM —> IgG

Question 288

Describe the electrophoresis band pattern of nephrotic syndrome

Answer 288

Decreased: - albumin, a1, B, and y globulin Increased: - a2 globulins

Question 289

Describe the electrophoresis band of APR

Answer 289

Increaed: - a1 - a2

Question 290

Describe the electrophoresis bands of multiple myeloma

Answer 290

Increase in y globulin-M spike

Question 291

Describe the kidneys importance

Answer 291

- play a vital role in maintaining levels of many substances in the human body, retaining critical components and eliminating what is not essential

Question 292

Describe renal function tests

Answer 292

- included in chemistry screening profiles to test for renal disease, water balance, and acid-base disorders

Question 293

What organs are in the urinary system?

Answer 293

- two kidneys - two uterers - bladder - urethra

Question 294

Describe the kidney structure

Answer 294

- divided into two distinct areas 1. The outer layer, or cortex 2. The inner layer, or medulla - each kidney contains approximately one to 1.5 million nephrons, the functional unit of the kidney

Question 295

Describe renal blood flow

Answer 295

- vital to renal function - supplied by renal artery - enters the nephrons through the afferent arteriole- - flows through glomerulus into efferent arteriole - blood is filtered in the glomerulus - filtrate flows through the proximal convoluted tubule (PCT)

Question 296

What is the Renal blood flow?

Answer 296

1. Renal artery 2. Afferent arteriole 3. Glomerulus 4. Efferent arteriole 5. Peritubular capillaries 6. Vasa recta 7. Renal vein

Question 297

What are 3 major renal functions?

Answer 297

1. Glomerular filtration 2. Tubular reabsorption 3. Tubular secretion

Question 298

Describe glomerular filtration

Answer 298

- enhanced by a number of factors - pressure in the glomerular capillaries is high because of the difference in size between the Afferent and efferent arterioles - basement membrane is negatively charged and large, negatively charged molecules (protein) are repelled

Question 299

Describe tubular reabsorption

Answer 299

- active transport - renal threshold - passive transport

Question 300

Describe active transport of tubular reabsorption

Answer 300

- substance to be reabsorbed must be combined with a carrier protein contained in the membranes of the renal tubular cells

Question 301

Describe renal threshold of tubular reabsorption

Answer 301

- concentration above which the substance cannot be totally reabsorbed and is excreted in the urine

Question 302

Describe passive transport of tubular reabsorption

Answer 302

- requires no energy - characterized by movement of substance from an area of high concentration to one of lower concentration - water and urea are always reabsorbed through passive transport

Question 303

Describe tubular secretion

Answer 303

- passage of substances from the Peritubular capillaries into the tubular filtrate

Question 304

What are the 2 major functions of tubular secretion?

Answer 304

- elimination of waste products not filtered by the glomerulus - regulation of acid-base balance in the Body through secretion of 90% of the hydrogen ions excreted by the kidney

Question 305

Describe Nonprotein Nitrogen (NPN)

Answer 305

Comprises the products of catabolism of proteins and nucleic acids, which contain nitrogen but are not part of a protein molecule

Question 306

What is the NPN of blood urea nitrogen (BUN)?

Answer 306

45%

Question 307

What is the NPN of amino acids?

Answer 307

20%

Question 308

What is the NPN of uric acid?

Answer 308

20%

Question 309

What is the NPN of creatinine?

Answer 309

5%

Question 310

What is the NPN of creatine?

Answer 310

1-2%

Question 311

What is the NPN of ammonia?

Answer 311

0.2%

Question 312

Describe Blood urea nitrogen (BUN)

Answer 312

- major nitrogen-containing metabolic product of protein catabolism in humans

Question 313

What is BUN formed from?

Answer 313

- exogenous protein: protein in diet - endogenous protein: protein from the breakdown of cells in the body

Question 314

Describe the direct relationship between urea and the glomerular filtration rate (GFR)

Answer 314

- in a patient with a normal to increased GFR, approximately 40% of the BUN is reabsorbed and 60% is excreted - in a well-hydrated patient, more BUN is excreted, resulting in a lower serum BUN - in a dehydrated patient, 70% of the BUN is increased and urine BUN is decreased

Question 315

What are the 3 variables that BUN is dependent on?

Answer 315

- urea concentration - glomerular filtration rate (GFR) - level of hydration

Question 316

What are clinical significances of BUN?

Answer 316

- azotemia —> an increased blood urea and other NPN compounds - uremia — an increased urea/BUN

Question 317

What are the categories of azotemia?

Answer 317

- prerenal - renal - postrenal

Question 318

Describe prerenal azotemia

Answer 318

- decreased renal blood flow - increased protein catabolism

Question 319

What would deceased renal blood flow lead to?

Answer 319

- congestive heart failure - dehydration - shock (from blood loss) - advanced cirrhosis - septic states

Question 320

What does increased protein catabolism lead to?

Answer 320

- muscle wasting (starvation) - GI hemorrhage - stress - steroids - uncontrolled diabetes mellitus - high fever

Question 321

What does renal azotemia lead to?

Answer 321

- uremia - acute kidney injury - glomerulonephritis - nephrotic syndrome - acute renal failure

Question 322

What does postrenal azotemia lead to ?

Answer 322

- tumors of the bladder or prostate gland - prostatic hypertrophy - gynecologic tumors - nephrolithiasis - severe infections

Question 323

Describe the BUN: creatinine (BUN:CR) ratio

Answer 323

- the normal ratio is between 12:0 to 20:1 - in renal disease, BUN and CR are both elevated proportionally - the ratio will fall within the normal range - a high ratio >20:1 to 30:1with a high BUN and a normal or only slightly elevated CR is associated with prerenal azotemia - high ratios with an elevated CR suggest postrenal obstruction (azotemia) or prerenal azotemia in addition to renal disease

Question 324

What are BUN methodologies?

Answer 324

- urease - berthelot’s reaction - Nesslers reaction - glutamate dehydrogenase (GLDH) - diacetyl or fearon reaction

Question 325

What does urease look like?

Answer 325

Urea + 2H2O —(urease)—> 2NH4 + CO3

Question 326

Describe Bethelot’s reaction

Answer 326

- the ammonium ion is reacted with phenol and hypochlorite in an alkaline medium to form indophenol blue, the chromagen which is measured - NH4 + 5 NaOCl + phenol —(NaOH)—> indophenol blue + 5NaCl + 5H2O

Question 327

Describe Nesslers reaction

Answer 327

- the addition of a double iodide compound (2HgI2 + 2KI) results in the formation of a yellow to orange brown compound with NH4+ 2HgI2 + 2KI + NH4 —> NH2HG2I3 + 4KI + NH4I

Question 328

Describe glutamate dehydrogenase (GLDH)

Answer 328

- is most commonly used. - the disappearance of NADPH is measure as a decrease in absorbance as NADPH is oxidized to NAD+ NH4 + 2-oxoglutarate + NADH —(glutamate dehydrogenase)—> NAD + glutamate + H2O

Question 329

Describe diacetyl or fearon reaction

Answer 329

- colorimetric reaction based on the condensation of diacetyl with urea to form the chromogen diazine Urea + diacetyl + H2O —(H+ strong acid)—> Diazine + 2H2O

Question 330

What is the reference range for BUN?

Answer 330

7-18 mg/dL

Question 331

What is the reference range for BUN on a. 24hr urine?

Answer 331

12-20 g/24h

Question 332

What type of diet increases BUN?

Answer 332

High protein

Question 333

What value of BUN is considered dehydrated?

Answer 333

<8 mg/dL

Question 334

What is the range of BUN that signifies impairment of glomerular filtration rate?

Answer 334

50-150 mg/dL

Question 335

What value of BUN. Is evidence of severe renal impairment?

Answer 335

150-200 mg/dL

Question 336

Describe conversion factor for BUN

Answer 336

- calculated using the molecular weight of BUN and nitrogen - BUN mw (60) - nitrogen (28)

Question 337

How to convert from urea to urea nitrogen?

Answer 337

Divide the mw of nitrogen by the mw of urea 28/60 for a factor of 0.467

Question 338

How to convert urea nitrogen to urea?

Answer 338

(60/28) is factor 2.14

Question 339

What amino acids synthesize creatinine in the liver?

Answer 339

- arginine - glyicine - methionine

Question 340

Describe creatinine

Answer 340

- readily filtered by the glomeruli and does not undergo and significant tubular reabsorption - waste product derived from creatine and creatine phosphatase Phosphocreatine + ADP —(creatine kinase)—> creatine + ATP Creatine —> creatinine + H2O

Question 341

Constancy of endogenous creatinine production is proportional to what?

Answer 341

- the muscle mass of the individual and it is released into the body fluids at a constant rate

Question 342

What are the 3 main variables that affect creatinine levels?

Answer 342

- relative muscle mass - creatine turnover - renal function

Question 343

Describe the clinical significance of creatinine

Answer 343

- creatinine is primarily an index of renal function —> measures that glomerular filtration rate (GFR) - increased serum creatinine is present when the formation or excretion of urine is impaired due to prerenal, renal or postrenal causes - creatinine levels in urine can be used to detect if a urine has been diluted - creatinine and BUN levels can be used to identify a fluid as urine

Question 344

What are the reference ranges of creatinine?

Answer 344

Men: 0.9-1.2 mg/dL Women: 0.6-1.1 mg/dL (because lower muscle mass) - decrease with age beginning in the fifth decade

Question 345

What are creatinine methodologies?

Answer 345

- Jaffe reaction - a kinetic method - creatininase (creatinine amidohydrolase) —> followed by creatinase, sarcosine, oxidase and peroxidase - creatinase —> second enzymatic procedure also fuses creatinase followed by creatine kinases, pyruvate kinase (PK), and lactate dehydrogenase (LD) —> creatinase —>CK—>PK—>LD

Question 346

Describe uric acid

Answer 346

- the major product of purine (adenine and guanine) catabolism in man and high primates —> produced in the liver from xanthine by the action of the enzyme xanthine oxidase Xanthine —(xanthine oxidase)—> uric acid

Question 347

What is uric acid formed from?

Answer 347

- exogenous nucleotides (dietary) - endogenous nucleotides (cells breaking down and being replaced

Question 348

What are clinical significance of uric acid?

Answer 348

- Hyperuricemia — a serum UA concentration of >7.0 mg/dL

Question 349

What are causes of hyperuricemia?

Answer 349

- increased dietary intake - overproduction of uric acid - underexcretion of uric acid - specific enzyme defects

Question 350

What are the reference ranges for uric acid?

Answer 350

Male: 3.5-7.2 mg/dL Female: 2.6-6.0 mg/dL

Question 351

What is the urinary filtrate flow?

Answer 351

1. Bowman’s capsule 2. PCT (proximal) 3. Descending loop of Henle 4. Ascending loop of Henle 5. DCT (distal) 6. Collecting duct 7. Renal calyces 8. Ureter 9. Bladder 10. Urethra

Question 352

What is associated with primary hyperuricemia?

Answer 352

Gout Idiopathic

Question 353

What is associated with secondary hyperuricemia?

Answer 353

- cytotoxic chemotherapy - radiation therapy - malignancy - acute or chronic renal disease, renal failure - increase tissue catabolism/starvation - glycogen storage disease - high purine diet - ethanol abuse - toxemia of pregnancy - severe exercise - poisons (lead) - drug therapy (diuretics,barbiturates) - Lesch-Nyhan syndrome

Question 354

Describe gout of uric acid

Answer 354

- inborn error of metabolism - predominantly in men 30 to 50 years of age - 7 time more common in men than women

Question 355

What are symptoms of gout?

Answer 355

- arthritis (pain, inflammation of the joints) - Nephropathy - nephrolithiasis

Question 356

What triggers gout attacks?

Answer 356

- alcohol - high-protein diets - stress - acute infection - surgery - certain medications

Question 357

What are uric acid methodologies?

Answer 357

- phosphotungstic acid - sodium carbonate - uricase

Question 358

Describe phosphotungstic acid of uric acid methodologies

Answer 358

Measures the development of a blue color (tungsten blue) as phosphotungstic acid (PTA) is reduced by uric acid in an alkaline medium

Question 359

Describe sodium carbonate of uric acid methodologies

Answer 359

Added to maintain the alkaline pH Uric acid + phosphotungstic acid —(Na2CO3)—> Allantoin + CO2 + Tungsten blue

Question 360

Describe uricase of uric acid methodologies

Answer 360

- catalyzes the oxidation of uric cid to allantoin - the decrease in absorbance at 293 nm, which is a peak absorbance for uric acid and one at which allantoin does not absorb - peroxidase and a dye (4-aminoantipyrene) is a second modification and the most common automated method

Question 361

Describe renal clearance test

Answer 361

- the rate at which the kidneys remove a substance from the plasma or blood - quantitative expression of the rate at which a substance is excreted by the kidneys in relation to the concentration of the same substance in the plasma usually expressed as mL cleared per minute

Question 362

Describe creatinine clearance test

Answer 362

- creatinine is a very good indicator of glomerular filtration rate for 3 reasons —> freely filtered by the glomeruli —> not reabsorbed by the tubules to a significant extent —> released into the plasma at a constant rate, resulting in constant plasma levels over 24 hours

Question 363

How is creatinine clearance calculated?

Answer 363

- CrCl is calculated using the serum and urine creatinine levels and the urine volume Clearance(x) = (U x V)/P U = urine concentration in mg/dL P = plasma concentration in mg/dL V = urine flow in mL/minute (1440 min/24hr)

Question 364

Describe creatinine clearance correction

Answer 364

- creatinine clearance has to be corrected to an adult body surface area (BAS) of 1.73 m2 - espcecially important from small or pediatric patients and obese patients - Dubois formula SA (surface area in m2) = W(kg)^0.425 x H(cm)^0.725 x 0.007184 * addd to CrCl equation [(U x V)/P] x (1.73 m2)/BSA m2 (normalization factor)

Question 365

What test has the largest source of error due to incomplete urine collection?

Answer 365

Creatinine clearance test

Question 366

What are the reference range of creatinine

Answer 366

Males: 97-137 mL/minute Females: 88-128 mL/minute

Question 367

Describe eGFR clearance tests

Answer 367

- use of an estimating or prediction equation to estimate glomerular filtration rate from the serum creatinine level in patients with chronic renal disease and those at risk for CKD - original modification of diet in renal disease (MDRD) study equation —> in pateints 18 years of age and older, the MDRD equation is the best means currently available to use creatinine values as a measure of renal function

Question 368

Describe protein:creatinine ratio clearance test

Answer 368

- normal protein excretion is <100-150 mg/24h - creatinine excretion is fairly constant at 12-20 mg of creatinine per kilogram of body weight per day - normal protein: creatinine ratio is <0.1 —> 100-150 mg protein/1000-1500 mg creatinine

Question 369

Describe insulin clearance test

Answer 369

- an endogenous, naturally occurring polysaccharide found in artichokes - insulin in injected and measured in serum and urine over three hours - no easily performed test for insulin measurement - difficult to meet the criteria for accurate testing

Question 370

Describe cystatin C clearance test

Answer 370

- single-chained, nonglycoslated, low-molecular-weight protein synthesized by all nucleated cells - freely filtered by the glomeruli and catabolized in the proximal convoluted tubules - produced at a constant rate - not affected by muscles mass, diet, race, age, or gender

Question 371

What are screening tests for renal disease?

Answer 371

- serum protein - B-microglobulin - low-molecular-weight proteins - urinalysis - microalbumin

Question 372

Describe serum protein screening for renal disease

Answer 372

- severe renal disease is characterized by decrease in total protein, especially the smaller-molecular-weight-proteins such as albumin - both serum total protein and albumin levels therefore will be decreased in some renal diseases

Question 373

Describe B-microglobulin screening of renal disease

Answer 373

- BMG - small, nonglycosylated protein found on the cell membrane of most nucleated cells - present in especially high levels in lymphocytes - increased in renal failure - used primarily to test for renal tubular function in renal transplant pateints when decreased tubular function indicates early rejection

Question 374

Describe low-molecular-weight proteins screening for renal disease

Answer 374

- a1-microglobulin - a2-microglobulin - B-trace protein - cystatin C

Question 375

Describe urinalysis screening for renal disease

Answer 375

- routine urinalysis may be the first indication of renal disease - reagent strip tests provide valuable information regarding renal function

Question 376

Describe protein test of urinalysis

Answer 376

- utilizes tetrabomphenol blue and is based on the “protein error of indicators”

Question 377

What is often the first sign of kidney disease?

Answer 377

Proteinuria

Question 378

What is blood or hemoglobin in the urine indicative of?

Answer 378

Renal or bladder disease

Question 379

What does presence of leukocytes in urine associated with?

Answer 379

Bacterial infection in the bladder or kidney

Question 380

What is nitrite detection used for in urinalysis?

Answer 380

- nitrate-reducing bacteria

Question 381

What is usually the first sign of renal disease?

Answer 381

- albumin in the urine - acknowledged to be an independent predictor of nephropathy in diabetes mellitus

Question 382

Describe glomerular disease

Answer 382

- associated primarily with damage to the glomeruli of the renal nephron - various renal disease are characterized by distinctive chemistry and urinalysis profiles

Question 383

Describe acute glomerulonephritis (AGN)

Answer 383

- characterized by rapid onset of symptoms that indicate damage to the glomeruli - most often associated with children and young adults following a group A streptococcal infection (strep infection)

Question 384

What are the symptoms of AGN?

Answer 384

- rapid onset - fever - malaise - nausea - oliguria - hematuria - proteinuria

Question 385

Describe secondary complications of glomerulonephritis

Answer 385

- edema —> especially periorbital, knees, ankles - hypertension from mild to moderate - electrolyte imbalance (Na+ and K+) - Renal function tests are abnormal with elevated BUN and creatinine and decreased GFR - as toxicity subsides, the urinalysis and renal function tests return to normal

Question 386

Describe Chronic Glomerulonephritis (CGN)

Answer 386

- associated with end stage of persistent glomerular damage with irreversible loss of renal tissue and chronic and renal failure

Question 387

What are the symptoms of CGN?

Answer 387

- edema - fatigue - hypertension - anemia - metabolic acidosis - proteinuria - decreased urine volume from oligura to Anuria

Question 388

Describe nephrotic syndrome

Answer 388

- may occur as a complication of glomerulonephritis or as a result of circulatory disorders

Question 389

What conditions can nephrotic syndrome be associated with?

Answer 389

- minimal charge nephropathy - focal segmental glomerulosclerosis (FGSG) - carcinoma - drugs - infection

Question 390

Describe symptoms of nephrotic syndrome

Answer 390

- Massive proteinuria - albuminuria - pitting edema - hyperlipidemia - hypoalbuminemia

Question 391

What are the hallmark sign nephrotic syndrome?

Answer 391

- low albumin and high lipids

Question 392

Describe pyelonephritis

Answer 392

- inflammatory process involving a bacterial infection of the renal tubules by gram-negative bacteria - ascending infection - usually does not cause permanent damage to the renal tubules

Question 393

What are the negative-gram bacteria found in pyelonephritis?

Answer 393

- escherichia Coli - klebsiella - proteus - enterobacter

Question 394

What are causes or conditions of pyelonephritis?

Answer 394

- incomplete emptying of bladder - vesicourelteral reflux - diabetes - urinary obstruction - catheterization

Question 395

Describe chronic pyelonephritis

Answer 395

-characterized by permanent scarring of the renal tubules - can lead to renal failure - most common cause is vesicoureteral reflux nephropathy

Question 396

What would the urinalysis of a patient with chronic pyelonephritis look like?

Answer 396

- alkaline pH - positive leukocyte esterase - bacteria (+/-) - proteinuria (moderate) - decreased specfic gravity - granular, waxy cast, broad, WBC, and renal cells casts - polyuria - nocturia

Question 397

Describe cystitis

Answer 397

- a bladder infection characterized by dysuria - more common in females than males - can progress to pyelonephritis if untreated or if treatment guidelines have not been adhered to

Question 398

What would a urinalysis of a patient with cystitis look like?

Answer 398

- small protein (<0.5 g/day) - hematuria - leukocyte esterase and nitrite positive - increased WBCs, bacteria, transitional epithelial cells - Absence of cellular casts

Question 399

What conditions are associated with chronic kidney disease (CKD)?

Answer 399

- hypertension - diabetes - autoimmune diseases - urinary tract and systemic infections - nephrolithiasis

Question 400

Describe the stages of CKD

Answer 400

At risk = GFR >90 (no markers of kidney damage) 1 = kidney damage with normal to increased GFR (>90) 2 = kidney damage with mild reduction of GFR (60-89) 3 = moderate reduction of GFR (30-59) 4 = severe reduction of GFR (15-29) 5 = kidney failure (<15 or on dialysis)

Question 401

Descibe renal failure

Answer 401

- acute increase in the serum creatinine level of 25%, or more and GFR 610 mL/min. - results from acute tubular necrosis from vasoconstriction, nephrotoxic agents and hemorrhaging

Question 402

What are signs of renal failure?

Answer 402

- decreased urine production - oliguria (6400 mL/day) - anuria

Question 403

Describe renal calculi

Answer 403

- solid aggregates of chemical or mineral salts formed in the renal tubules, renal pelvis, ureters or bladder - can cause ulceration and bleeding - more common in males than females - 75% calcium oxalate with or without phosphate - 15% magnesium ammonium phosphate - 6% urate (uric acid) - 1-2% cystine - 2-3% mixtures

Question 404

What are the four factors that influence the formation of kidney stones?

Answer 404

1. Increased in concentration of chemical salts as a result of dehydration or increase in salts in the diet 2. Change in urinary pH 3. Urinary stasis 4. Presence of a foreign body

Question 405

What are symptoms of renal calculi?

Answer 405

- nausea - vomiting - intense pain from the kidney, and downward toward the abdomen, genitalia, and legs

Question 406

Describe diabetes mellitus

Answer 406

- some 45% of type 1 diabetes mellitus patients develop nephropathy within 15 - 20 years of diagnosis - diabetic nephropathy is diagnosed when a patient with diabetes presents with proteinuria with no evidence of a urinary tract infection - diabetes is the leading cause of renal failure

Question 407

Describe dialysis

Answer 407

- dialysis or kidney transplant may be the only treatment options available for patients with acute renal failure or ESRD - is a process whereby larger macromolecules are separated from low-molecular-weight compounds by their rate of diffusion through a semipermeable membrane

Question 408

Describe hemolysis (HD)

Answer 408

- synthetic membrane is in a machine outside the body - traditional and most common method - patients blood minus the toxic products is returned to circulation - dialysate contains the waste products is discarded

Question 409

Describe peritoneal dialysis (PD)

Answer 409

- peritoneal wall acts as the dialysis membrane - dialysate is introduced and removed through gravity - requires continuous (24 hours a day, 7 days a week) treatment - not as effective as hemodialysis

Question 410

What must be closely evaluated in dialysis patients?

Answer 410

- well-being - cardiovascular risk - nutritional status - degree of achievable ultrafiltration

Question 411

Describe Urea kinetic modeling (UKM)

Answer 411

- evaluates dialysis patients - consider age, sex, presence of diabetes, or cardiovascular disease, and creatinine clearance - most widely used method in the assessment of dialysis adequacy

Question 412

Describe complications of dialysis

Answer 412

- patients on dialysis are prone to a number of diseases —> 40% show evidence of coronary artery disease —> 75% show left ventricular hypertrophy - anemia is common in people with kidney disease - dialysis patients with ESRD also have poor appetite, and protein metabolism is decreased because of inflammation and chronic acidosis —> results in malnutrition