CC Flashcards

Question

The fourth most abundant cation in the body and the second most prevalent intracellular cation: Calcium Magnesium Potassium Sodium

Answer 1

Type 1 diabetes mellitus

Answer 2

Fructosamine Fructosamine assays are the most widely used to assess short-term (3- to 6-week) glycemic control because the average half-life of the proteins is 2 to 3 weeks.

Answer 3

HDL HDL plays a key role in reverse cholesterol transport, the process by which excess cholesterol is returned from tissues to the liver, where it is reused or excreted in bile.

Answer 4

LpX lipoprotein LpX is an abnormal lipoprotein found in patients with obstructive biliary disease and in patients with familial lecithin/cholesterol acyltransferase (LCAT) deficiency.

Answer 5

Chylomicrons and VLDL VLDL and chylomicrons are the most lipid-rich lipoprotein classes in human blood. This fact leaves them as the most buoyant in plasma. These lipoproteins have a density of less than 1.006 kg/L (density measurement). LDL particles are smaller in size and in lipid content, causing their density to range from 1.006 to 1.063 kg/L. HDL, the densest lipoprotein, ranges from 1.063 to 1.210 kg/L.

Answer 6

Tangier disease Tangier disease is a rare autosomal recessive disorder characterized by complete absence of HDL due to a mutation in the ABCA1 gene on chromosome 9. In the homozygous state, patients present with low or undetectable HDL in plasma, hepatosplenomegaly, peripheral neuropathy, orange tonsils, and premature coronary disease.

Answer 7

Prealbumin Prealbumin plays a significant role in the metabolism of vitamin A by complexing with the retinol-binding protein (RBP), which, in turn, complexes with vitamin A to transport it through the body.

Answer 8

Alpha1-acid glycoprotein

Answer 9

Iron deficiency anemia A striking elevation of transferrin in the β-region sometimes occurs in patients suffering from iron deficiency anemia. The increase in transferrin corresponds to increased IBC, and the percent saturation is low.

Answer 10

Lower Enzymes lower the activation energies of the chemical reactions that they catalyze, so as to cause greatly enhanced rates of reaction. They do not become modified in these reactions and do not affect the equilibrium between reactants and products in the reaction.

Answer 11

Isoenzymes Many enzymes have isoenzymes, called isozymes, of different forms that catalyze the same reaction. These different forms occur because of differences in the amino acid sequences of enzymes. Despite these differences in sequence, the enzymes fold to the same three-dimensional structures and frequently exhibit similar affinities for and catalytic rates with substrates.

Answer 12

Cofactors In addition to the basic enzyme structure, a nonprotein molecule, called a cofactor, may be necessary for enzyme activity. Inorganic cofactors, such as chloride or magnesium ions, are called activators. A coenzyme is an organic cofactor, such as NAD.

Answer 13

Catalytic mechanism

Answer 14

LD4 and LD5 In myocardial damage, the predominant isozymes that become elevated in serum are LD1 and LD2; in liver or skeletal muscle disease, the LD4 and LD5 isozymes become elevated predominantly in serum.

Answer 15

LD6 Another band detected in electrophoresis and termed LD6 can be seen; this probably represents alcohol dehydrogenase, which can also metabolize lactate.

Answer 16

Hemolysis Gilbert's syndrome Crigler-Najjar syndrome

Answer 17

Dubin-Johnson syndrome Biliary obstruction

Answer 18

Fall below normal references ranges due to inadequate protein feeding The common recommendation for neonatal testing is that specimens are collected when the newborn is at least 3 days old and after 24 hours of protein feeding in order to adequately supply nutrients to produce thyroid hormones. Given the common practice of dismissing mother and newborn baby within 48 hours of the mother’s admission, it is likely that thyroxine levels may occasionally fall below normal reference ranges due to inadequate protein feeding rather than congenital hypothyroidism.

Answer 19

Acute toxicity Acute toxicity is usually associated with a single, short-term exposure to a substance, the dose of which is sufficient to cause immediate toxic effects.

Answer 20

Chronic toxicity Chronic toxicity is usually associated with repeated frequent exposure for extended periods for greater than 3 months and possibly years, at doses that are insufficient to cause an immediate acute response. In many instances, chronic exposure is related to an accumulation of the toxicant or the toxic effects within the individual. Chronic toxicity may affect different systems than those associated with acute toxicity.

Answer 21

Phencyclidine PHENCYCLIDINE Used almost exclusively as a drug of abuse, this drug is traded on the streets under the name of angel dust or angel hair

Answer 22

Lysergic acid diethylamide Lysergic acid diethylamide (LSD) is a semisynthetic indolalkylamine and a hallucinogen. LSD toxicity levels are low, and deaths are generally due to trauma secondary to errors in the user’s judgment. Panic reactions—a bad trip—are the most common adverse reactions.

Answer 23

Ethosuximide (Zarontin) Ethosuximide is the drug of choice for absence (petit mal) seizures unaccompanied by other types of seizures. It is preferred over valproic acid, at least initially, because hepatotoxicity is a rare but serious side effect of valproic acid.

Answer 24

Theophylline and theobromine Anti-asthmatic drugs, such as theophylline and theobromine, are used for treatment of neonatal breathing disorders or of respiratory conditions that affect adults or children, such as asthma.

Answer 25

Ethanol Ethanol is probably the most common drug of abuse and is frequently responsible for the presentation of patients with altered mental status to hospitals and emergency rooms. Peak plasma concentrations are usually reached within 1 hour after ingestion.

Answer 26

Whole blood Unlike many other toxins, lead is generally measured in whole blood rather than in serum or plasma, because most of the circulating lead is bound within the blood cells.

Answer 27

Quality systems Quality assessment (QA) in the laboratory, a program that monitors the total testing process with the aim of providing the highest quality patient care; formerly called quality assurance. Quality control (QC) a system that verifies the reliability of analytical test results through the use of standards, controls, and statistical analysis. Quality systems (QS) in an institution, a comprehensive program in which all areas of operation are monitored to ensure quality with the aim of providing the highest quality patient care.

Answer 28

Trend TREND: an indication of error in the analysis, detected by a progressive drift of control values in one direction for at least 5 consecutive runs SHIFT: an abrupt change from the established mean indicated by the occurrence of all control values on one side of the mean ------ Assaying control specimens and standards along with patient specimens serves several major functions: 1. Provides a guide to the functioning of equipment, reagents, and individual technique 2. Confirms the accuracy of testing when compared with reference values 3. Detects an increase in the frequency of both high and low minimally acceptable values (dispersion) 4. Detects any progressive drift of values to one side of the average value for at least 3 days (trends) 5. Demonstrates an abrupt shift or change from the established average value for 3 days in a row (shift)

Answer 29

Fixed-angle centrifuge Fixed angle–head centrifuges are used when rapid centrifugation of solutions containing small particles is needed; an example is the microhematocrit centrifuge. Ultracentrifuges are high-speed centrifuges generally used for research projects, but for certain clinical uses, a small air-driven ultracentrifuge is available that operates at 90,000 to 100,000 rpm and generates a maximum RCF of 178,000 g. Ultracentrifuges are often refrigerated.

Answer 30

All of these COMPONENTS OF A QUALITY SYSTEMS PROGRAM A comprehensive quality systems program is designed to follow a specimen all the way through the testing process, from the time a test is ordered, through specimen collection and testing to reporting, charting, and delivery and use of results. The scope of QS programs differs among laboratories, but in general QS programs are broad, ongoing, and encompass evaluation of: 1. Personnel qualifications, training, and competency 2. Quality Assessment components including preanalytical (before test) factors, analytical factors and QC methods and postanalytical (after test) factors 3. Proficiency testing

Answer 31

Instrument maintenance and calibration Analytical Factors Affecting Laboratory Test Results Quality assessment programs also evaluate analytical factors that can affect the actual test procedure. Many of these factors fall under the umbrella of QC. Analytical factors include: 1. Instrument maintenance and calibration 2. Use of standards and procedural controls 3. Techniques and test components associated with performing the test procedure (reagents, laboratory water, pipetting, timing, etc.) 4. Interfering substances or conditions 5. Statistical analysis of control results An example of an analytical error is inaccurate sampling caused by problems with an instrument’s automatic sampler, perhaps because of dirt or protein buildup in the sampling probe. The error might be detected when control values show an abrupt or steady change. Such an error can usually be prevented by performing recommended maintenance tasks.

Answer 32

Proficiency testing Proficiency testing (PT) is another component of laboratory quality programs. Laboratories that perform nonwaived procedures are required to subscribe to an external PT program. At regular intervals during the year, the PT agency sends blind samples to the laboratory. These are samples that have been assayed multiple times by the PT agency. The subscribing laboratory analyzes these blind samples and sends the results to the PT agency. The subscribing laboratory’s results are then compared to the PT agency’s assayed values and to the results of peer laboratories participating in the PT program. Participating laboratories receive a report evaluating their performance.

Answer 33

Presumptive test A procedure with minimal complexity, instrumentation, and personnel requirements so that the results can be quickly determined.

Answer 34

Presumptive test A procedure with minimal complexity, instrumentation, and personnel requirements so that the results can be quickly determined.

Answer 35

Definitive test Highly sensitive and specific test in which results can be used as legal evidence

Answer 36

Turbidimetry Turbidimetry measures light blocked as a decrease in the light transmitted through the solution; dependent on particle size and concentration.

Answer 37

Very short wavelengths Ultraviolet (UV) light has very short wavelengths and infrared (IR) light has very long wavelengths. When all visible wavelengths of light (400-700 nm) are combined, white light results.

Answer 38

Increased specificity and increased sensitivity Fluorometric methods are extremely sensitive and highly specific. Because of this extreme sensitivity, reagents used must be of a higher degree of purity than is required for spectroscopy, because even slight traces of impurities may fluoresce.

Answer 39

Mie scatter Mie scatter - large particles scattering light predominantly a in the forward direction Raleigh scatter - small particles scattering light in all directions with maximum scatter forward and backward

Answer 40

Raleigh scatter Mie scatter - large particles scattering light predominantly a in the forward direction Raleigh scatter - small particles scattering light in all directions with maximum scatter forward and backward

Answer 41

Fluorescence intensity decreases In general, fluorescence intensity decreases with increasing temperature by approximately 1 to 5% per degree Celsius.

Answer 42

Volumetric transfer pipettes

Answer 43

Ostwald-Folin transfer pipettes

Answer 44

Ultracentrifuge

Answer 45

Cytocentrifuge This type of preparation can be used for blood, urine, body fluid, or any other liquid specimen that can be spread on a slide. An advantage of this technology is that only a small amount of sample is used, producing evenly distributed cells that can then be stained for microscopic study. The slide produced can be saved and examined at a later time, in contrast to “wet” preparations, which must be examined immediately.

Answer 46

Increased potassium and calcium Fist pumping during venipuncture ↑ K+, lactic acid, Ca2+, phosphorus; ↓ pH Pumping of the fist before venipuncture should be avoided because it causes an increase in plasma potassium, phosphate, and lactate concentrations. Lowering of blood pH by accumulation of lactate causes the plasma ionized calcium concentration to increase.

Answer 47

20 mg/dL Hemolysis is generally a preanalytical problem that can be avoided. It is graded based on visible presence of hemoglobin, when greater than 20 mg/dL, and it is often graded as mild, moderate, or gross hemolysis.

Answer 48

5 to 15 mg/dL erroneously higher Glucose measurements can be 5 to 15 mg/dL erroneously higher by reducing methods than by more accurate enzymatic methods that are highly specific for glucose.

Answer 49

Colorimetric: endpoint

Answer 50

Colorimetric

Answer 51

Five bands Standard SPE separates the protein into 5 distinct bands but, by modifying the electrophoretic parameters, proteins can be further separated into as many as 12 bands. The modification, known as high-resolution protein electrophoresis (HRE), uses a higher voltage coupled with a cooling system in the electrophoretic apparatus and a more concentrated buffer.q

Answer 52

Deficiency in the bilirubin conjugation enzyme system The increased levels of unconjugated bilirubin will cause the infant to appear jaundiced. Generally, this condition persists for only a short period because the enzyme system usually becomes functional within several days after birth. Neonatal physiological jaundice resulting from an enzyme deficiency is hepatic in origin.

Answer 53

Celite Support media that may be used for electrophoretic separations include agarose gel, starch gel, cellulose acetate, and acrylamide. Celite provides the inert supporting phase in gas-liquid chromatography.

Answer 54

Ponceau S Amido black 10B, Coomassie brilliant blue, and Ponceau S are dyes that are used to stain serum proteins after electrophoresis. Oil red O and fat red 7B are dyes that are used to stain lipoproteins following electrophoresis.

Answer 55

Albumin Using standard SPE methods, serum proteins appear in five bands: albumin travels farthest to the anode, followed by α1-globulins, α2-globulins, β-globulins, and γ-globulins, in that order.

Answer 56

Bisalbuminemia Bisalbuminemia is a congenital disorder that does not exhibit any clinical manifestations. The only sign of this disorder is the splitting of albumin into two distinct bands when serum is subjected to electrophoresis.

Answer 57

Ceruloplasmin CERULOPLASMIN - ALPHA2-GLOBULIN

Answer 58

Bromcresol purple (BCP) BCP is more specific for albumin than BCG. However, BCG is the method used most often. One reason for this is that renal dialysis patients produce an organic acid that competes with BCP for the binding site on albumin, causing a falsely low result.

Answer 59

Fetal fibronectin The level of fetal fibronectin increases in the secretions of the cervix and vagina. When this occurs prematurely, the increase in fetal fibronectin is used to predict risk of premature birth. Inhibin A, alpha-fetoprotein, human chorionic gonadotropin, and unconjugated estriol are used together in the quadruple test to assess risk for such disorders as Down syndrome.

Answer 60

Down syndrome An increased AFP level in maternal serum is associated with such disorders as neural tube defects, spina bifida, and fetal distress. A decreased AFP level in maternal serum is characteristic of Down syndrome.

Answer 61

Progesterone SCREENING FOR BIRTH DEFECTS 1. Triple test: AFP, HCG and ESTRIOL 2. Quadruple (QUAD) screen: AFP, HCG, ESTRIOL and INHIBIN-A

Answer 62

Mancini or the endpoint RID The endpoint method requires that all Ag diffuse from the well and the concentration of the Ag is related to the square of the diameter of the precipitin ring; the standard curve is plotted and a line of the best fit is computed. To ensure that all of the Ag has diffused, the incubation time is 48 to 72 hours, depending on the molecular weight of the Ag; for example, IgG quantitation requires 48 hours, and IgM requires 72 hours. For those performing RID, the endpoint method is favored because of its stability and indifference to temperature variations; however, turnaround time is longer compared with the kinetic method.

Answer 63

Fahey-McKelvey or the kinetic RID The kinetic method requires that all rings be measured at a fixed time of 18 hours; a sample with a greater concentration will diffuse at a faster rate and will be larger at a fixed time. The diameter of the precipitin ring is plotted against the Ag concentration on a logarithmic scale.

Answer 64

In the fasting state, approximately 12 hours after eating

Answer 65

Uptake The FTI has been largely replaced by the direct measurement of free T4 by immunoassay, dialysis, or ultrafiltration.

Answer 66

> 200 mg/dL, > 400 mg/dL Errors in LDL-C become noticeable at triglyceride levels >2.26 mmol/L (200 mg/dL) and become unacceptably large at triglyceride levels >4.52 mmol/L (400 mg/dL).

Answer 67

Over 400 mg/dL The equation should not be used with triglyceride values exceeding 400 mg/dL because the VLDL composition is abnormal, making the [triglyceride/5] factor inapplicable.

Answer 68

Competitive inhibitors Competitive inhibitors: compete with the substrate for the active site of the enzyme and prevent formation of product, but have a higher Km than the preferred substrate and can be overcome by addition of more substrate. Noncompetitive inhibitors: bind on a different active site of the enzyme than the substrate and so cannot be overcome by addition of more substrate, but prevent formation of product despite the enzyme-substrate complex. Uncompetitive inhibitors: bind to the enzyme-substrate complex and prevent the formation of product. This type of inhibition is also reversible.

Answer 69

Noncompetitive inhbitors Competitive inhibitors: compete with the substrate for the active site of the enzyme and prevent formation of product, but have a higher Km than the preferred substrate and can be overcome by addition of more substrate. Noncompetitive inhibitors: bind on a different active site of the enzyme than the substrate and so cannot be overcome by addition of more substrate, but prevent formation of product despite the enzyme-substrate complex. Uncompetitive inhibitors: bind to the enzyme-substrate complex and prevent the formation of product. This type of inhibition is also reversible.

Answer 70

Uncompetitive inhibitors

Answer 71

Fixed-time method In the fixed-time method, the reactants are combined, the reaction proceeds for a designated time, the reaction is stopped (usually by inactivating the enzyme with a weak acid), and a measurement of the amount of reaction that has occurred is made.

Answer 72

Kinetic method In continuous-monitoring or kinetic assays, multiple measurements, usually of absorbance change, are made during the reaction, either at specific time intervals (usually every 30 or 60 seconds) or continuously by a continuous-recording spectrophotometer.

Answer 73

LD-5 is the most labile isoenzyme. Loss of activity occurs more quickly at 4°C than at 25°C. Serum samples for LD isoenzyme analysis should be stored at 25°C and analyzed within 24 hours of collection.

Answer 74

Para-nitrophenylphosphate ALP catalyzes the hydrolysis of para-nitrophenyl phosphate forming phosphate and free 4-nitrophenyl (4-NPP) which, under alkaline conditions has very intense yellow color.

Answer 75

92% For monovalent cations or anions the contribution to osmolality is approximately 92%. Other serum electrolytes, serum proteins, glucose, and urea contribute to the remaining 8%

Answer 76

Hyponatremia due to increased water retention

Answer 77

Hypernatremia due to excess water loss

Answer 78

Sample hemolysis, thrombocytosis, prolonged tourniquet use or excessive fist clenching

Answer 79

Parathyroid hormone, calcitonin and vitamin D

Answer 80

Angiotensin II

Answer 81

Fluid retention, low serum sodium

Answer 82

Increased unmeasured cations or decreased unmeasured anions Decreased anion gaps of less than 10 mmol/L: either an increase in unmeasured cations (Ca2+, Mg2+) or a decrease in the unmeasured anions Anion gap exceeds 16 mmol/L Indication of increased concentrations of the unmeasured anions (PO4 3−, SO4 2−, protein ions)

Answer 83

10 mOsm/kg The degree of increase in osmolality due to ethanol is expressed as the difference between the measured and the calculated osmolality; the difference is called the osmolar gap. Serum osmolality increases by about 10 mOsm/kg for each 60 mg/dL increase in serum ethanol.

Answer 84

On ice, no clots, no air bubbles Specimen requirements for blood gas analysis include the following. 1. Arterial blood is collected in a glass or plastic syringe. Capillary specimens can also be used (blood must be “arterialized”). 2. Lyophilized or liquid heparin is the preferred anticoagulant. 3. No air bubbles should exist in the sample because they lower the pCO2 value. 4. The specimen must be placed on ice and transported to the laboratory in 15 minutes at 4◦C and tested immediately. Otherwise, pH values decrease, and pCO2 values increase. 5. Blood clots are unacceptable.

Answer 85

pO2 will fall 7% and pCO2 will rise 3%

Answer 86

Thyroxine T4 is the predominant form of the thyroid hormones secreted into the circulation, having a concentration in the plasma significantly greater than T3. However, in terms of physiological activity, T3 must be considered because it is four to five times more potent than T4.

Answer 87

Thyroid-stimulating hormone (TSH) TSH is the American Thyroid Association’s recommended screening test.

Answer 88

No decrease in serum growth hormone concentration 90 minutes after oral glucose administration Following an overnight fast, a 100-gram oral glucose load will cause a large drop in serum growth hormone in a normal individual, but will not suppress in patients with acromegaly.

Answer 89

Single-stranded DNA The target DNA must be denatured to single-stranded DNA before it can serve as a template for the PCR reaction.

Answer 90

42.5 grams