Chapter 7 Flashcards
(138 cards)
1
Q
General methods for common automated and manual assays include the use of- (6)
A
-photometry
-spectrometry
-ion-selective electrodes (ISEs)
-electrophoresis
-nephelometry
-immunoassays
2
Q
measurement techniques fall into one of four categories-
A
-Spectrometry
-Luminescence
-Electroanalytical methods
-Chromatography
3
Q
Photometry employs ____ & ____ ______ to determine the concentrations of various substances.
A
-color
-color variation
4
Q
the measurement of the luminous intensity of light, or the amount of luminous light falling on a surface from a light source-
A
photometry
5
Q
The concentration of an unknown sample is determined by measuring-
A
light absorption at a certain wavelength & comparing it with light absorption by standard solutions measured at the same time & wavelength
6
Q
Light is a type of-
A
radiant energy
7
Q
light travels in the form of-
A
waves
8
Q
The wavelength of light is the distance between-
A
waves
9
Q
the term light is used to describe-
A
radiant energy with wavelengths visible to the human eye or bordering on those visible to the human eye
10
Q
Electromagnetic radiation includes a spectrum of energy on the left side- (3)
A
-short-wavelength
-highly energetic gamma rays
-x-rays
11
Q
Electromagnetic radiation includes a spectrum of energy on the right side-
A
wavelengths of radio frequencies
12
Q
Visible light passes between these frequencies, with the color violet at about ____ wavelength & red at ___ wavelength-
A
-400-nm
-700-nm
13
Q
appx. wavelength of not visible (ultraviolet light)-
A
<380 nm
14
Q
appx. wavelength of violet light-
A
380 - 440 nm
15
Q
appx. wavelength of blue light-
A
440 - 500 nm
16
Q
appx. wavelength of green light-
A
500 - 580 nm
17
Q
appx. wavelength of yellow light-
A
580 - 600 nm
18
Q
appx. wavelength of orange light-
A
600 - 620 nm
19
Q
appx. wavelength of red light-
A
620 - 750
20
Q
appx. wavelength of not visible (infrared light)-
A
> 750
21
Q
Beer’s law states that the concentration of a substance is directly proportional to-
A
the amount of light absorbed
22
Q
Beer’s law states that the concentration of a substance is inversely proportional to-
A
the logarithm of the transmitted light
23
Q
Beer’s law is the basis for the use of photometry in-
A
quantitative measurement
24
Q
In absorbance spectrophotometry, the absorbance units or values for several different concentrations of a standard solution are determined by-
A
spectrophotometry & plotted on graph paper
25
The resulting graph in absorbance spectrophotometry is known as- (3)
-standard calibration curve
-standard curve
-Beer-Lambert (Beer’s) law plot
26
Absorbance is an expression of-
amount of light absorbed by a solution
27
absorbance =
2 minus the logarithm of the percent transmittance
28
units used to express the readings obtained by the electronic measuring device are either-
-absorbance units
-percent transmittance units
29
Absorbance values are directly proportional to the concentration of-
the solution & can be plotted on graph paper to give a straight line
30
Percent transmittance is the amount of light that passes through a-
colored solution compared with the amount of light that passes through a blank or standard solution
31
Transmitted light does not decrease in direct proportion to-
concentration or color intensity of the solution being measured
32
Percent transmittance readings plotted against concentration will not give-
a straight line on linear graph paper, but will on semilogarithmic graph paper
33
Standard curves are defined as-
a graph with absorption (A) or %T plotted on the y-axis (vertical axis), & increasing concentrations of standard along the x-axis (horizontal axis)
34
If Beer’s law is followed, the resulting line representing absorbance versus concentration will be-
straight
35
Once a standard curve is developed for a test method on a particular spectrophotometer, it should be checked-
periodically to determine that it is still good
36
Semilogarithmic (semilog) graph paper is used to plot-
%T readings from the photometer
37
The horizontal axis (x-axis) of semilog graph paper is a ______ scale-
linear
38
The vertical axis (y-axis) of semilog graph paper is a _______ scale-
log
39
Concentrations of the standard solutions are plotted on the ______ axis-
horizontal
40
The transmittance or absorbance readings from the photometer are plotted along the ______ axis-
vertical
41
Criteria for a good standard curve- (3)
-The line is straight
-The line connects all points
-The line goes through the origin, or intersect, of the two axes
42
plotting a standard curve- (3)
-Note the intervals on the graph paper
-Axes must be properly labeled
-Review sources of error
43
Once the standard curve has been plotted, it is used to calculate-
concentrations of any unknowns that were included in the same batch as the standards used to make the graph
44
Parts essential to all spectrophotometers- (4)
-Light source
-Wavelength isolator (filter)
-Cuvettes (absorption cells or photometer tubes)
-Electronic measuring device (commonly a photoelectric cell plus galvanometer)
45
Quality control tests for spectrophotometers- (3)
-Wavelength accuracy
-Stray light
-Linearity
46
A beam of light is directed at a flat surface, and the amount of light reflected is measured in a-
reflectance spectrophotometer
47
Light reflected from the surface of a colorimetric reaction is used to measure the amount of-
unknown colored product generated in the reaction
48
Quality control for single-test instruments is integrated into the instruments by-
manufacturer
49
Manufacturing processes, shipping & handling, or storage problems can affect-
measurements
50
A lamp generates light, which passes through- (2)
-filter
-series of slits
51
A lamp generates light, which is focused on-
the test surface
52
Some light is absorbed by-
the filter
53
the remaining light that isn't absorbed is-
reflected
54
The reflected light then passes through a series of-
slits & lenses & on to the photodetector device, where the amount of light is measured & recorded as a signal
55
Common point-of-care testing and self-testing instruments include those for-
quantitation of blood glucose (employing single-test methodology) in maintaining good diabetic control
56
In urinalysis testing, various instruments use-
dry-reagent reflectance spectrophotometry
57
Chemistry and therapeutic drug-monitoring analyzer systems also employ-
single-test methodology technology
58
Fluorescent light is the result of-
the absorbance of a photon of radiant energy by a molecule
59
When excess energy is ejected as a photon, the result is-
fluorescence emission, which can be measured
60
The intensity of the fluorescence is determined by using a-
fluorometer, sometimes called a spectrofluorometer or fluorescence spectrophotometer
61
Only a few compounds can fluoresce, and of those that do, not all photons absorbed will be converted to-
fluorescent light
62
Nephelometry is the measurement of-
light that has been scattered
63
Tubidimetry is the measurement of-
a loss in the intensity of light transmitted through a solution because of the light being scattered. (The solution becomes turbid)
64
Turbidimetry will measure light that is-
scattered, not absorbed or reflected by the particles in the suspension
65
Nephelometers are used to detect-
the amount of light scattered
66
When specific antigen-coated latex particles acting as reaction intensifiers are agglutinated by their-
corresponding antibody
67
the increased light scatter of a solution can be measured by-
nephelometry as the macromolecular complexes form
68
Formation of a macromolecular complex is a prerequisite for-
nephelometric protein quantitation
69
The amount of scattered light is proportional to-
the number of insoluble complexes
70
the amount of scattered light can be quantitated by comparing-
unknown patient values with standards of known protein concentration
71
An infrared high-performance light-emitting diode is used as-
the light source
72
advantages of Nephelometry- (2)
-automated system that is rapid, reproducible, relatively simple to operate, & very common in higher-volume labs.
-has many applications in immunology laboratory
73
disadvantages of Nephelometry- (2)
-high initial equipment cost
-Interfering substances may cause protein denaturation & erroneous test results
74
Laser light is the most common light source used in-
flow cytometers
75
laser light is the most common light source used in flow cytometers because of its properties of-
-intensity
-stability
-monochromaticity
76
Cells in suspension are stained with-
an appropriate fluorochrome, such as an immunologic reagent or a dye that stains a specific component
77
Fluorescent dyes used in flow cytometry bind or react with the-
cellular component of interest
78
The stained cells then pass through the-
laser beam in single file
79
The stained cells then pass through the laser beam in single file. The laser activates- (2)
-dye
-cell fluoresces
80
Applications of labels include- (3)
-enzyme immunoassays (EIAs)
-chemiluminescence
-fluorescent substances
81
Chemiluminescent reactions have replaced-
most radioimmunoassays in the clinical lab
82
Immunoassays use-
antigen-antibody reactions
83
An antigen may be used as a reagent to detect-
the presence of antibodies in the serum of a patient
84
Immunoassays can be divided into- (2)
-heterogeneous immunoassays
-homogeneous immunoassays
85
Homogeneous immunoassays are faster and easier to-
automate than heterogeneous immunoassays & have competitive formats
86
Enzyme immunoassay (EIA) can test for- (2)
-specific antigen
-antigen-specific antibody
87
Enzyme-linked immunosorbent assay (ELISA), is designed to detect-
antigens or antibodies by producing an enzyme-triggered color change
88
EIAs for ____ & _____ detection-
-antigen detection
-antibody detection
89
Lateral or vertical-flow immunoassays also known as-
immunochromatography assay
90
immunochromatography is a versatile and rapid method for-
visual detection of antigen in a blood sample on a test strip
91
Lateral or vertical-flow immunoassays has components of-
a test strip
92
Immunofluorescent technique labeling can demonstrate-
the complexing of antigens & antibodies
93
in Direct immunofluorescent assay
A conjugated antibody is used to detect-
antigen-antibody reactions at a microscopic level
94
Inhibition immunofluorescent assay is a blocking test in which-
an antigen is first exposed to unlabeled antibody, then to labeled antibody, & is finally washed and examined
95
Indirect immunofluorescent assay uses-
immunoglobulins’ reaction with antiimmunoglobulins
96
Immunofluorescent techniques- (3)
-Time-resolved fluoroimmunoassay
-Fluorescence polarization immunoassay
-Fluorescence in situ hybridization
97
alternative Immunofluorescent Labeling Techniques- (2)
-Signal amplification technology
-Magnetic labeling technology
98
Chemiluminescence is the emission of light by -
molecules in an excited state with a limited amount of emitted heat (luminescence) as the result of a chemical reaction
99
New chemiluminescence systems use-
chemiluminescent labels & substrates rather than older fluorescent labels and detection systems
100
New chemiluminescence systems are used to detect- (4)
-proteins
-viruses
-oligonucleotides
-genomic nucleic acid sequences
101
proteins, viruses, oligonucleotides, and genomic nucleic acid sequences in- (4)
-immunoassays
-DNA probe assays
-DNA sequencing
-electrophoresis
102
Potential Benefits of Immunoassay Automation have the ability to-
provide better service with less staff
103
Potential Benefits of Immunoassay Automation save on- (4)
-controls
-duplicates
-dilutions
-repeats
104
Potential Benefits of Immunoassay Automation eliminates- (2)
-radioactive labels
-associated regulations
105
Immunoassay Automation has a better- (2)
-shelf life of reagents, with less disposal caused by outdating
-sample identification with bar code labels & primary tube sampling
106
Immunoassay Automation of sample delivery is-
possible
107
Amplification techniques in molecular biology
Polymerase chain reaction (PCR) is a molecular diagnostic technique that-
amplifies low levels of specific DNA sequences in a sample to higher quantities suitable for further analysis
108
Other amplification techniques- (4)
-Strand displacement amplification
-Transcription-mediated amplification
-Nucleic acid sequence–based amplification
-Ligase chain reaction nucleic acid amplification
109
Analysis of amplification products- (2)
-Conventional analysis & other techniques
-DNA sequencing & hybridization techniques
110
Blotting protocols-
Western blot
111
Microarrays are miniature gene fragments attached to-
glass chips
112
microarrays product of bonding or direct synthesis of-
numerous specific DNA probes on a stationary, often silicon-based support
113
microarrays glass chip may be tailored to-
particular disease processes
114
the term electrochemistry is used when-
chemical energy is converted to an electrical current (a flow of electrons) in a galvanic cell
115
Electrochemical reactions are characterized by-
a loss of electrons (oxidation) at the positive pole (anode) & a simultaneous gain of electrons (reduction) at the negative pole (cathode).
116
Electroanalytical chemistry uses electrochemistry for-
analysis purposes, such as to measure ions, drugs, hormones, metals, and gases
117
Potentiometry compares-
the potential of one electrode to another
118
Ion-selective electrodes (ISEs) are designed to be-
sensitive toward individual ions
119
The relationship between the ionic concentration (activity) and the electrode potential is given by-
the Nernst equation
120
The term pH refers to the concentration of-
hydrogen ions ([H+], also called protons) in a solution
121
For aqueous solutions, the scale ranges from-
0 to 14, with pure water in the middle at 7
122
The more acid a solution-
the lower is the pH (0 to 6.9)
123
alkaline solutions come in at-
the high end of the scale 7.1 to 14
124
Types of meters- (3)
-Analog meters
-Digital meters
-Self-calibrating, direct-reading ion meters
125
Coulometry measures-
the amount of current passing between two electrodes in an electrochemical cell
126
The principle of coulometry involves the application of-
a constant current to generate a titrating agent
127
the time required to titrate a sample at constant current is measured and-
is related to the amount of analyte in the sample
128
The amount of current is directly proportional to the amount of-
substance produced or consumed by the electrode
129
Electrophoresis is the migration of-
charged solutes or particles in an electrical field
130
When charged particles are made to move-
differences in molecular structure can be seen because different molecules have different velocities in an electrical field
131
The assay using electrophoresis involves-
the movement of charged particles when an external electrical current is produced in a liquid environment
132
Electrophoresis is a technique for-
separation and purification of ions, proteins, and other molecules of biochemical interest
133
In chromatography, mixtures of solutes dissolved in a common solvent are separated from one another by-
a differential distribution of the solutes between two phases
134
two main categories of chromatography are-
-gas chromatography
-liquid chromatography
135
chromatography-
in which the solute phase is in a gaseous state
136
liquid chromatography-
in which the solute phase is a solution or liquid
137
The same steps needed to perform an analysis from the central laboratory are needed for- point-of-care testing (POCT)
point-of-care testing (POCT)
138
steps needed to perform analysis from the central laboratory- (5)
-Instrument validation
-Periodic assay calibration
-Quality control testing
-Operator training
-Proficiency testing
