Immunlogy-Immunologic Procedures Flashcards
1
Q
- The interaction between an individual antigen
and antibody molecule depends upon several
types of bonds such as ionic bonds, hydrogen
bonds, hydrophobic bonds, and van der Waals
forces. How is the strength of this attraction
characterized?
A. Avidity
B. Affinity
C. Reactivity
D. Valency
A
B. Affinity
2
Q
- A laboratory is evaluating an enzyme-linked
immunosorbent assay (ELISA) for detecting an
antibody to cyclic citrullinated peptide (CCP),
which is a marker for rheumatoid arthritis. The
laboratory includes serum from healthy volunteers
and patients with other connective tissue diseases
in the evaluation. These specimens determine
which factor of the assay?
A. Sensitivity
B. Precision
C. Bias
D. Specificity
A
D. Specificity
3
Q
- The detection of precipitation reactions depends
on the presence of optimal proportions of antigen
and antibody. A patient’s sample contains a large
amount of antibody, but the reaction in a test system
containing antigen is negative. What has happened?
A. Performance error
B. Low specificity
C. A shift in the zone of equivalence
D. Prozone phenomenon
A
D. Prozone phenomenon
4
Q
- Which part of the radial immunodiffusion (RID)
test system contains the antisera?
A. Center well
B. Outer wells
C. Gel
D. Antisera may be added to any well
A
C. Gel
5
Q
- What is the interpretation when an Ouchterlony
plate shows crossed lines between wells 1 and 2
(antigen is placed in the center well and antisera in
wells 1 and 2)?
A. No reaction between wells 1 and 2
B. Partial identity between wells 1 and 2
C. Nonidentity between wells 1 and 2
D. Identity between wells 1 and 2
A
C. Nonidentity between wells 1 and 2
6
Q
- Why is a chemiluminescent immunoassay (CIA) or
enzyme immunoassay (EIA) the method of choice
for detection of certain analytes, such as hormones,
normally found in low concentrations?
A. Because of low cross reactivity
B. Because of high specificity
C. Because of high sensitivity
D. Because test systems may be designed as both
competitive and noncompetitive assays
A
C. Because of high sensitivity
7
Q
- What comprises the indicator system in an indirect
ELISA for detecting antibody?
A. Enzyme-conjugated antibody + chromogenic
substrate
B. Enzyme conjugated antigen + chromogenic
substrate
C. Enzyme + antigen
D. Substrate + antigen
A
A. Enzyme-conjugated antibody + chromogenic
substrate
8
Q
- What outcome results from improper washing of a
tube or well after adding the enzyme–antibody
conjugate in an ELISA system?
A. Result will be falsely decreased
B. Result will be falsely increased
C. Result will be unaffected
D. Result is impossible to determine
A
B. Result will be falsely increased
9
Q
- What would happen if the color reaction phase is
prolonged in one tube or well of an ELISA test?
A. Result will be falsely decreased
B. Result will be falsely increased
C. Result will be unaffected
D. Impossible to determine
A
B. Result will be falsely increased
10
Q
- The absorbance of a sample measured by ELISA is
greater than the highest standard. What corrective
action should be taken?
A. Extrapolate an estimated value from the highest
reading
B. Repeat the test using a standard of higher
concentration
C. Repeat the assay using one half the volume of the
sample
D. Dilute the test sample
A
D. Dilute the test sample
11
Q
- A patient was suspected of having a
lymphoproliferative disorder. After several
laboratory tests were completed, the patient was
found to have an IgMκ paraprotein. In what
sequence should the laboratory tests leading to
this diagnosis have been performed?
A. Serum protein electrophoresis (SPE) followed
by immunofixation electrophoresis (IFE)
B. Immunoglobulin levels followed by SPE
C. Total lymphocyte count followed by
immunoglobulin levels
D. Immunoglobulin levels followed by urine protein
electrophoresis
A
A. Serum protein electrophoresis (SPE) followed
by immunofixation electrophoresis (IFE)
12
Q
- An IFE performed on a serum sample showed a
narrow dark band in the lanes containing anti-γ
and anti-λ. How should this result be interpreted?
A. Abnormally decreased IgG concentration
B. Abnormal test result demonstrating monoclonal
IgGλ
C. Normal test result
D. Impossible to determine without densitometric
quantitation
A
B. Abnormal test result demonstrating monoclonal
IgGλ
13
Q
- Which type of nephelometry is used to measure
immune complex formation almost immediately
after reagent has been added?
A. Rate
B. Endpoint
C. Continuous
D. One dimensional
A
A. Rate
14
Q
- An immunofluorescence microscopy assay (IFA)
was performed, and a significant antibody titer was
reported. Positive and negative controls performed
as expected. However, the clinical evaluation of the
patient was not consistent with a positive finding.
What is the most likely explanation of this
situation?
A. The clinical condition of the patient changed
since the sample was tested
B. The pattern of fluorescence was misinterpreted
C. The control results were misinterpreted
D. The wrong cell line was used for the test
A
B. The pattern of fluorescence was misinterpreted
15
Q
- What corrective action should be taken when an
indeterminate pattern occurs in an indirect IFA?
A. Repeat the test using a larger volume of sample
B. Call the physician
C. Have another medical laboratory scientist read
the slide
D. Dilute the sample and retest
A
D. Dilute the sample and retest
