Medical Laboratory Technician Exam Immunology and Serology 3

Question 1

Which test is considered the gold standard confirmatory test for HIV infection?

Accepted Answer

Western blot / immunoblot

Answer

Western blot (or newer HIV-1/HIV-2 differentiation immunoassay) is used to confirm a repeatedly reactive HIV screen result.

Question 2

A latex agglutination test for Cryptococcus neoformans detects which antigen?

Accepted Answer

Polysaccharide capsular antigen

Answer

The cryptococcal antigen test detects polysaccharide capsular antigen of C. neoformans in serum or CSF.

Question 3

Secretory IgA differs from serum IgA primarily in that secretory IgA:

Accepted Answer

Contains a J chain and secretory component

Answer

Secretory IgA is a dimer joined by a J chain and protected by a secretory component added during transcytosis across epithelial cells.

Question 4

In immunofluorescence testing for ANA, a homogeneous (diffuse) pattern is most commonly associated with antibodies against:

Accepted Answer

dsDNA and histones

Answer

A homogeneous ANA pattern reflects antibodies to dsDNA and histones that bind uniformly throughout the nucleus.

Question 5

Which immunoglobulin class is the first to be produced during a primary immune response?

Accepted Answer

IgM

Answer

IgM is synthesized first during a primary immune response because it requires no class-switch recombination.

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