3.8

Question 1

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

Answer 1

D. 1:2, 1:6, 1:12

Question 2

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

Answer 2

A. Activated partial thromboplastin time (APTT)

Question 3

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

Answer 3

C. Neutrophils, macrophages, complement, fibrinogen, C-reactive protein

Question 4

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

Answer 4

A. Serum IgG, IgA, and IgM

Question 5

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

Answer 5

C. Measurement of immunoglobulins

Question 6

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

Answer 6

D. Patient has immunodeficiency with hyper-M; perform immunoglobulin levels

Question 7

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

Answer 7

B. Treponemal test such as MHA-TP on serum

Question 8

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

Answer 8

A. The antibody response is not sufficient to be detected at this stage

Question 9

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

Answer 9

B. EBV serological panel

Question 10

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

Answer 10

C. Repeat hepatitis testing in a few weeks

Question 11

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

Answer 11

D. HBsAg, negative; anti-HBc, negative—she may donate

Question 12

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

Answer 12

B. Positive rubella test for IgM

Question 13

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

Answer 13

C. Rheumatoid factor caused a false-positive test result

Question 14

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

Answer 14

C. Testing too soon after surgery

Question 15

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

Answer 15

D. ELISA tests for specific antibodies

Question 16

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

Answer 16

A. Anti CCP

Question 17

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

Answer 17

B. It prevents graft-versus-host disease

Question 18

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

Answer 18

D. T cells

Question 19

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

Answer 19

A. Ovarian malignancy has recurred

Question 20

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

Answer 20

C. Results are inconclusive

Question 21

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

Answer 21

C. Toxo IgG avidity

Question 22

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

Answer 22

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

Question 23

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

Answer 23

C. No; it is likely the patient has recently received a hepatitis B booster vaccination and could have these results

Question 24

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

Answer 24

D. Refer the discrepant specimens for testing by another method