3.7 Flashcards
A patient had surgery for colorectal cancer, after which he received chemotherapy for 6 months. The test for carcinoembryonic antigen (CEA) was normal at this time. One year later, the bimonthly CEA was elevated (above 10 ug/mL). An examination and biopsy revealed then recurrence of a small tumor. What was the value of the results provided by the CEA test in this clinical situation?
A. Diagnostic information
B. Information for further treatment
C. Information on the immunologic response of the patient
D. No useful clinical information in this case
B. Information for further treatment
A carbohydrate antigen 125 assay (CA-125) was performed on a woman with ovarian cancer. After treatment, the levels fell significantly. An examination performed later revealed the recurrence of the tumor, but the CA 125 levels remained low. How can this finding be explained?
A. Test error
B. CA-125 was the wrong laboratory test; α-fetoprotein (AFP) is a better test to monitor ovarian cancer
C. CA-125 may not be sensitive enough when used alone to monitor tumor development
D. CA-125 is not specific enough to detect only one
type of tumor
C. CA-125 may not be sensitive enough when used alone to monitor tumor development
What is the correct procedure upon receipt of a test request for human chorionic gonadotropin (hCG) on the serum from a 60-year-old man?
A. Return the request; hCG is not performed on men
B. Perform a qualitative hCG test to see if hCG is present
C. Perform the test; hCG may be increased in testicular tumors
D. Perform the test but use different standards and controls
C. Perform the test; hCG may be increased in testicular tumors
Would an hCG test using a monoclonal antibody against the β-subunit of hCG likely be affected by an increased level of follicle-stimulating hormone (FSH)?
A. Yes, the β-subunit of FSH is identical to that of hCG
B. No, the test would be specific for the β-subunit of hCG
C. Yes, a cross reaction would occur because of structural similarities
D. No, the structure of FSH and hCG are not at all similar
B. No, the test would be specific for the β-subunit of hCG
Which of the following substances, sometimes used as a tumor marker, is increased two- or threefold in a normal pregnancy?
A. Alkaline phosphatase (ALP)
B. Calcitonin
C. Adrenocortocotropic hormone (ACTH)
D. Neuron-specific enolase
A. Alkaline phosphatase (ALP)
What is an advantage of performing a prostatespecific antigen (PSA) test for prostate cancer?
A. PSA is stable in serum and not affected by a digital-rectal examination
B. PSA is increased only in prostatic malignancy
C. A normal serum level rules out malignant prostatic disease
D. The percentage of free PSA is elevated in persons with malignant disease
A. PSA is stable in serum and not affected by a digital-rectal examination
Which method is the most sensitive for quantitation of AFP?
A. Double immunodiffusion
B. Electrophoresis
C. Enzyme immunoassay
D. Particle agglutination
C. Enzyme immunoassay
How is HLA typing used in the investigation of genetic diseases?
A. For prediction of the severity of the disease
B. For genetic linkage studies
C. For direct diagnosis of disease
D. Is not useful in this situation
B. For genetic linkage studies
Select the best donor for a man, blood type AB, in need of a kidney transplant.
A. His brother, type AB, HLA matched for class II antigens
B. His mother, type B, HLA matched for class I antigens
C. His cousin, type O, HLA matched for major class II antigens
D. Cadaver donor, type O, HLA matched for some class I and II antigens
A. His brother, type AB, HLA matched for class II antigens
Interpret the following microcytotoxicity results:
A9 and B12 cells damaged; A1 and Aw19 cells intact.
A. Positive for A1 and Aw19; negative for A9 and B12
B. Negative for A1 and Aw19; positive for A9 and B12
C. Error in test system; retest
D. Impossible to determine
B. Negative for A1 and Aw19; positive for A9 and B12
Which method, classically used for HLA-D typing, is often used to determine the compatibility between a living organ donor and recipient?
A. Flow cytometry
B. Mixed lymphocyte culture (MLC)
C. Primed lymphocyte test (PLT)
D. Restriction fragment length polymorphism (RFLP)
B. Mixed lymphocyte culture (MLC)
Cells type negative for all HLA antigens in a complement-dependent cytotoxicity assay. What is the most likely cause?
A. Too much supravital dye was added
B. Rabbit complement is inactivated
C. All leukocytes are dead
D. Antisera is too concentrated
B. Rabbit complement is inactivated
What method may be used for tissue typing instead of serological HLA typing?
A. PCR
B. Southern blotting
C. RFLP
D. All of these options
D. All of these options
