immunology-Immunology Problem Solving Flashcards
1
Q
- Which of the following serial dilutions contains an
incorrect factor?
A. 1:4, 1:8, 1:16
B. 1:1, 1:2, 1:4
C. 1:5, 1:15, 1:45
D. 1:2, 1:6, 1:12
A
D. 1:2, 1:6, 1:12
2
Q
- A patient was tested for syphilis by the RPR
method and was reactive. An FTA-ABS test was
performed and the result was negative. Subsequent
testing showed the patient to have a high titer of
anticardiolipin antibodies (ACAs) by the ELISA
method. Which routine laboratory test is most
likely to be abnormal for this patient?
A. Activated partial thromboplastin time (APTT)
B. Antismooth muscle antibodies
C. Aspartate aminotransferase (AST)
D. C3 assay by immunonephelometry
A
A. Activated partial thromboplastin time (APTT)
3
Q
- Inflammation involves a variety of biochemical
and cellular mediators. Which of the following
may be increased within 72 hours after an initial
infection?
A. Neutrophils, macrophages, antibody, complement,
α1-antitrypsin
B. Macrophages, T cells, antibody, haptoglobin,
fibrinogen
C. Neutrophils, macrophages, complement,
fibrinogen, C-reactive protein
D. Macrophages, T cells, B cells, ceruloplasmin,
complement
A
C. Neutrophils, macrophages, complement,
fibrinogen, C-reactive protein
4
Q
- An 18-month-old boy has recurrent sinopulmonary
infections and septicemia. Bruton’s X-linked
immunodeficiency syndrome is suspected. Which
test result would be markedly decreased?
A. Serum IgG, IgA, and IgM
B. Total T-cell count
C. Both B- and T-cell counts
D. Lymphocyte proliferation with
phytohemagglutinin stimulation
A
A. Serum IgG, IgA, and IgM
5
Q
- A patient received 5 units of fresh frozen plasma
(FFP) and developed a severe anaphylactic
reaction. He has a history of respiratory and
gastrointestinal infections. Post-transfusion studies
showed all 5 units to be ABO-compatible. What
immunologic test would help to determine the
cause of this transfusion reaction?
A. Complement levels, particularly C3 and C4
B. Flow cytometry for T-cell counts
C. Measurement of immunoglobulins
D. NBT test for phagocytic function
A
C. Measurement of immunoglobulins
6
Q
- An IFE revealed excessive amounts of polyclonal
IgM and low concentrations of IgG and IgA. What
is the most likely explanation of these findings and
the best course of action?
A. Proper amounts of antisera were not added;
repeat both tests
B. Test specimen was not added properly; repeat
both procedures
C. Patient has common variable immunodeficiency;
perform B-cell count
D. Patient has immunodeficiency with hyper-M;
perform immunoglobulin levels
A
D. Patient has immunodeficiency with hyper-M;
perform immunoglobulin levels
7
Q
- SITUATION: A 54-year-old man was admitted
to the hospital after having a seizure. Many
laboratory tests were performed, including an
RPR, but none of the results were positive. The
physician suspects a case of late (tertiary) syphilis.
Which test should be performed next?
A. Repeat RPR, then perform VDRL
B. Treponemal test such as MHA-TP on serum
C. VDRL on CSF
D. No laboratory test is positive for late (tertiary)
syphilis
A
B. Treponemal test such as MHA-TP on serum
8
Q
- A patient came to his physician complaining of a
rash, severe headaches, stiff neck, and sleep
problems. Laboratory tests of significance were an
elevated sedimentation rate (ESR) and slightly
increased liver enzymes. Further questioning of the
patient revealed that he had returned from a
hunting trip in upstate New York 4 weeks ago. His
physician ordered a serological test for Lyme
disease, and the assay was negative. What is the
most likely explanation of these results?
A. The antibody response is not sufficient to be
detected at this stage
B. The clinical symptoms and laboratory results are
not characteristic of Lyme disease
C. The patient likely has an early infection with
hepatitis B virus
D. Laboratory error has caused a false-negative result
A
A. The antibody response is not sufficient to be
detected at this stage
9
Q
- A 19-year-old girl came to her physician
complaining of a sore throat and fatigue. Upon
physical examination, lymphadenopathy was
noted. Reactive lymphocytes were noted on
the differential, but a rapid test for IM
antibodies was negative. Liver enzymes were
only slightly elevated. What test(s) should be
ordered next?
A. Hepatitis testing
B. EBV serological panel
C. HIV confirmatory testing
D. Bone marrow biopsy
A
B. EBV serological panel
10
Q
- A patient received 2 units of RBCs following
surgery. Two weeks after the surgery, the patient
was seen by his physician and exhibited mild
jaundice and slightly elevated liver enzymes.
Hepatitis testing, however, was negative. What
should be done next?
A. Nothing until more severe or definitive clinical
signs develop
B. Repeat hepatitis testing immediately
C. Repeat hepatitis testing in a few weeks
D. Check blood bank donor records and contact
donor(s) of transfused units
A
C. Repeat hepatitis testing in a few weeks
11
Q
- A hospital employee received the final dose of the
hepatitis B vaccine 3 weeks ago. She wants to
donate blood. Which of the following results are
expected from the hepatitis screen, and will she be
allowed to donate blood?
A. HBsAg, positive; anti-HBc, negative—she may
donate
B. HBsAg, negative; anti-HBc, positive—she may
not donate
C. HBsAg, positive; anti-HBc, positive—she may
not donate
D. HBsAg, negative; anti-HBc, negative—she may
donate
A
D. HBsAg, negative; anti-HBc, negative—she may
donate
12
Q
- A pregnant woman came to her physician with a
maculopapular rash on her face and neck. Her
temperature was 37.7°C (100°F). Rubella tests for
both IgG and IgM antibody were positive. What
positive test(s) would reveal a diagnosis of
congenital rubella syndrome in her baby after
birth?
A. Positive rubella tests for both IgG and IgM
antibody
B. Positive rubella test for IgM
C. Positive rubella test for IgG
D. No positive test is revealed in congenital rubella
syndrome
A
B. Positive rubella test for IgM
13
Q
- SITUATION: A patient with RA has acute
pneumonia but a negative throat culture. The
physician suspects an infection with Mycoplasma
pneumoniae and requests an IgM-specific antibody
test. The test is performed directly on serial
dilutions of serum less than 4 hours old. The result
is positive, giving a titer of 1:32. However, the test
is repeated 3 weeks later, and the titer remains at
1:32. What best explains these results?
A. IgM-specific antibodies do not increase fourfold
between acute and convalescent serum
B. The results are not significant because the initial
titer was not accompanied by a positive test for
cold agglutinins
C. Rheumatoid factor caused a false-positive test
result
D. Insufficient time had elapsed between
measurement of acute and convalescent
samples
A
C. Rheumatoid factor caused a false-positive test
result
14
Q
- A patient has a prostate-specific antigen level of
60 ng/mL the day before surgery to remove a
localized prostate tumor. One week following
surgery, the serum PSA was determined to be
8 ng/mL by the same method. What is the most
likely cause of these results?
A. Incomplete removal of the malignancy
B. Cross reactivity of the antibody with another
tumor antigen
C. Testing too soon after surgery
D. Hook effect with the PSA assay
A
C. Testing too soon after surgery
15
Q
- A patient with symptoms associated with SLE and
scleroderma was evaluated by immunofluorescence
microscopy for ANAs using the HEp-2 cell line as
substrate. The cell line displayed a mixed pattern
of fluorescence that could not be separated by
serial dilutions of the serum. Which procedure
would be most helpful in determining the
antibody profile of this patient?
A. Use of a different tissue substrate
B. Absorption of the serum using the appropriate
tissue extract
C. Ouchterlony technique
D. ELISA tests for specific antibodies
A
D. ELISA tests for specific antibodies
16
Q
- A patient with joint swelling and pain tested
negative for serum RF by both latex agglutination
and ELISA methods. What other test would help
establish a diagnosis of RA in this patient?
A. Anti CCP
B. ANA testing
C. Flow cytometry
D. Complement levels
A
A. Anti CCP
17
Q
- What is the main advantage of the recovery and
reinfusion of autologous stem cells?
A. It slows the rate of rejection of transplanted cells
B. It prevents graft-versus-host disease
C. No HLA testing is required
D. Engraftment occurs in a more efficient sequence
A
B. It prevents graft-versus-host disease
18
Q
- A transplant patient began to show signs of
rejection 8 days after receipt of the transplanted
organ, and the organ was removed. What immune
elements might be found in the rejected organ?
A. Antibody and complement
B. Primarily antibody
C. Macrophages
D. T cells
A
D. T cells
19
Q
- A patient with ovarian cancer who has been treated
with chemotherapy is being monitored for
recurrence using serum CA-125, CA-50, and CA
15–3. Six months after treatment the CA 15–3 is
elevated, but the CA-125 and CA-50 remain low.
What is the most likely explanation of these findings?
A. Ovarian malignancy has recurred
B. CA 15–3 is specific for breast cancer and
indicates metastatic breast cancer
C. Testing error occurred in the measurement of
CA 15–3 caused by poor analytical specificity
D. The CA 15–3 elevation is spurious and probably
benign
A
A. Ovarian malignancy has recurred
20
Q
- An initial and repeat ELISA test for antibodies to
HIV-1 are both positive. A Western blot shows a
single band at gp160. The patient shows no
clinical signs of HIV infection, and the patient’s
CD4 T-cell count is normal. Based upon these
results, which conclusion is correct?
A. Patient is diagnosed as HIV-1-positive
B. Patient is diagnosed as HIV-2-positive
C. Results are inconclusive
D. Patient is diagnosed as HIV-1-negative
A
C. Results are inconclusive
21
Q
- A woman who has been pregnant for 12 weeks is
tested for toxoplasmosis. Her IgM ELISA titer is
2.6 (reference range < 1.6), and her IgG ELISA
value is 66 (reference range < 8). The physician
asks you if these results indicated an infection
during the past 12 weeks. Which of the following
tests would you recommend to determine if the
woman was infected during her pregnancy?
A. Toxo PCR on amniotic fluid
B. Toxo IgM on amniotic fluid
C. Toxo IgG avidity
D. Amniotic fluid culture
A
C. Toxo IgG avidity
22
Q
- On January 4, a serum protein electrophoresis on
a specimen obtained at your hospital in North
Dakota from a 58-year-old patient shows a band
at the β-γ junction. The specimen was also
positive for rheumatoid factor. You recommend
that an immunofixation test be performed to
determine if the band represents a monoclonal
immunoglobulin. Another specimen is obtained
2 weeks later by the physician in his office
30 miles away, and the whole blood is submitted
to you for the IFE. The courier placed the whole
blood specimen in an ice chest for transport. In
this specimen, no β-γ band is seen in the serum
protein lane, and the IgM lane is very faint. The
rheumatoid factor on this specimen was negative.
The physician wants to know what’s wrong with
your laboratory. Your response is:
A. Nothing’s wrong with our laboratory; the patient
had an infection 2 weeks ago that has cleared up
B. Something’s wrong with our laboratory—we
likely mislabeled one of the specimens; please
resubmit a new specimen and we will test it at
no charge
C. You will run a second specimen using a
2-mercaptoethanol treatment that will
eliminate IgM aggregates and allow for
more sensitive monoclonal IgM detection
D. The physician should redraw another specimen
from the patient and this time separate the serum
from the clot in his office before sending the
specimen in by courier
A
D. The physician should redraw another specimen
from the patient and this time separate the serum
from the clot in his office before sending the
specimen in by courier
23
Q
- A dialysis patient is positive for both hepatitis B
surface antigen and hepatitis B surface antibody.
The physician suspects a laboratory error. Do you
agree?
A. Yes; the patient should not test positive for both
HBsAg and HBsAb
B. No; incomplete dialysis of a patient in the core
window phase of hepatitis B infection will yield
this result
C. No; it is likely the patient has recently received a
hepatitis B booster vaccination and could have
these results
D. Perhaps; a new specimen should be submitted to
clear up the confusion
A
C. No; it is likely the patient has recently received a
hepatitis B booster vaccination and could have
these results
24
Q
- You are evaluating an ELISA assay as a replacement
for your immunofluorescent antinuclear antibody
test. You test 50 specimens in duplicate on each
assay. The ELISA assay uses a HEp-2 extract as its
antigen source. The correlation between the ELISA
and the IFA tests is only 60% (30 of 50 specimens
agree). Which of the following is the next best
course of action?
A. Test another 50 specimens
B. Perform a competency check on the
technologists who performed the tests
C. Order a new lot of both kits and then retest on
the new lots
D. Refer the discrepant specimens for testing by
another method
A
D. Refer the discrepant specimens for testing by
another method
