Medical Technologist Test Immunology and Serology 3

Question 1

Which antibody test is the gold standard for confirming Epstein-Barr virus (EBV) as the cause of infectious mononucleosis?

Accepted Answer

EBV-specific antibodies (VCA IgM/IgG, EBNA)

Answer

EBV-specific serology measuring VCA IgM, VCA IgG, EA, and EBNA antibodies provides definitive confirmation of EBV infection and disease stage.

Question 2

In flow cytometry, T-helper cells are distinguished from cytotoxic T cells primarily by:

Accepted Answer

Specific surface marker (CD4 vs. CD8) expression

Answer

Flow cytometry uses fluorochrome-conjugated monoclonal antibodies against CD4 and CD8 surface markers to distinguish T-helper from cytotoxic T cell subsets.

Question 3

A speckled ANA pattern with high-titer anti-U1 RNP antibodies is the hallmark of which autoimmune disease?

Accepted Answer

Mixed connective tissue disease (MCTD)

Answer

Anti-U1 RNP antibodies producing a speckled ANA pattern are the defining serological marker of mixed connective tissue disease.

Question 4

The direct antiglobulin test (DAT) is used to detect:

Accepted Answer

IgG or complement coating patient RBCs in vivo

Answer

The DAT detects IgG or C3d coating patient red blood cells in vivo and is used to diagnose immune hemolytic anemias and hemolytic transfusion reactions.

Question 5

Which tumor marker is most significantly elevated in hepatocellular carcinoma?

Accepted Answer

AFP (alpha-fetoprotein)

Answer

AFP is markedly elevated in hepatocellular carcinoma and non-seminomatous germ cell tumors; it is the primary tumor marker used for HCC surveillance.

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Medical Technologist Test Immunology and Serology 3