CSMLS CSMLS Immunology and Serology

Question 1

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

Accepted Answer

IgM

Answer

IgM is the first antibody produced during a primary immune response due to its pentameric structure enabling early complement activation.

Question 2

In an enzyme-linked immunosorbent assay (ELISA), the signal is generated by:

Accepted Answer

An enzyme conjugated to an antibody

Answer

In ELISA, an enzyme-conjugated antibody reacts with a substrate to produce a measurable colorimetric, fluorescent, or luminescent signal.

Question 3

The complement pathway initiated by antigen-antibody complexes is the:

Accepted Answer

Classical pathway

Answer

The classical complement pathway is activated by antigen-antibody (immune) complexes binding to C1q.

Question 4

A prozone phenomenon in agglutination testing occurs when:

Accepted Answer

Antibody is in excess causing false-negative results

Answer

The prozone effect occurs when antibody excess prevents lattice formation, resulting in a false-negative agglutination reaction.

Question 5

Which serological test is the gold standard for confirming HIV infection?

Accepted Answer

Western blot

Answer

Western blot is used as the confirmatory test for HIV infection because it detects antibodies to specific viral proteins.

CSMLS - Canadian Society for Medical Laboratory Science Practice Test