CMLA Immunology & Serology 2

Question 1

What principle does the ELISA (Enzyme-Linked Immunosorbent Assay) use to detect antibodies or antigens?

Accepted Answer

Enzyme-labeled antibodies producing a colorimetric signal

Answer

ELISA uses enzyme-conjugated antibodies that catalyze a substrate reaction, producing a measurable color change proportional to antigen or antibody concentration.

Question 2

In serological testing, agglutination indicates:

Accepted Answer

Cross-linking of particulate antigens by antibodies causing visible clumping

Answer

Agglutination occurs when antibodies form bridges between multiple particulate antigens (bacteria, red blood cells), causing visible clumping.

Question 3

What is the purpose of including a positive control in a serological assay?

Accepted Answer

To verify the test system produces a positive result with known positive material

Answer

A positive control confirms the assay is functioning correctly by demonstrating it can produce the expected positive result with a known positive specimen.

Question 4

In indirect fluorescent antibody (IFA) testing, the fluorescent-labeled secondary antibody binds to:

Accepted Answer

The patient's primary antibody already bound to antigen

Answer

In IFA, the fluorescent secondary antibody binds to the patient's (primary) antibody, which is already complexed with the antigen on the substrate.

Question 5

What does a serum antibody titer measure?

Accepted Answer

The highest dilution of serum still showing a positive reaction

Answer

A titer is the reciprocal of the highest serum dilution that still yields a detectable (positive) reaction, reflecting relative antibody concentration.

(CMLA) Certified Medical Laboratory Assistant Practice Test

(CMLA) Certified Medical Laboratory Assistant Practice Test

CMLA Immunology & Serology 2