3.8 Immunology Problem-Solving Flashcards
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
D. 1:2, 1:6, 1:12
A patient was tested for syphilis by the RPR method and was reactive. A TP-PA test was performed and the result was negative. Subsequent testing showed the patient to have a high titer of 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. Anti–smooth muscle antibodies
C. Aspartate aminotransferase (AST)
D. C3 assay by immunonephelometry
A. Activated partial thromboplastin time (APTT)
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
C. Neutrophils, macrophages, complement, fibrinogen, C-reactive protein
An 18-month-old boy has recurrent sinopulmonary infections and septicemia. Bruton thymidine kinase deficiency 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. Serum IgG, IgA, and IgM
A patient received 5 units of 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 Igs
D. NBT test for phagocytic function
C. Measurement of Igs
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 CD40 ligand (CD154) analysis
D. Patient has immunodeficiency with hyper-M; perform CD40 ligand (CD154) analysis
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 was positive. The physician suspects a case of late (tertiary) syphilis. Which test should be performed next?
A. Repeat RPR, followed by VDRL
B. Treponemal test, such as TP-PA on serum
C. VDRL on CSF
D. No laboratory test is positive for late (tertiary) syphilis
B. Treponemal test, such as TP-PA on serum
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 early-stage HBV infection
D. Laboratory error has caused a false-negative result
A. The antibody response is not sufficient to be detected at this stage
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 antibodies to IM 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
B. EBV serological panel
A patient received 2 units of RBCs following surgery. Two weeks after the surgery, the patient was seen by his physician and was found to have 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
C. Repeat hepatitis testing in a few weeks
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
D. HBsAg, negative; anti-HBc, negative—she may donate
