Laboratory Science Immunology and Serology

Question 1

What does the ANA (antinuclear antibody) test detect, and what condition is it associated with?

Accepted Answer

Autoantibodies against nuclear components; associated with systemic lupus erythematosus (SLE)

Answer

ANA detects autoantibodies targeting nuclear antigens (DNA, histones, ribonucleoproteins); a positive ANA with high titer is the hallmark screening test for SLE and other connective tissue diseases.

Question 2

Which immunoglobulin is the first antibody produced during primary immune response?

Accepted Answer

IgM

Answer

IgM is the first immunoglobulin produced during primary immune response and is the largest antibody (pentamer); it's detected in acute infections and gradually replaced by IgG in secondary responses.

Question 3

What is the rheumatoid factor (RF) test measuring?

Accepted Answer

IgM autoantibodies directed against the Fc region of IgG

Answer

Rheumatoid factor is typically IgM autoantibodies against the Fc region of IgG; elevated RF supports rheumatoid arthritis diagnosis but is not specific (also elevated in infections and other autoimmune diseases).

Question 4

A reactive RPR (Rapid Plasma Reagin) test should be confirmed with which more specific test for syphilis?

Accepted Answer

FTA-ABS (fluorescent treponemal antibody absorption) test

Answer

RPR is a non-treponemal screening test prone to biological false positives; confirmation requires a treponemal-specific test like FTA-ABS or TP-PA that detects antibodies to T. pallidum antigens.

Question 5

Which blood group antigen system is most clinically important for transfusion compatibility?

Accepted Answer

ABO and Rh (D antigen) systems

Answer

ABO incompatibility causes immediate intravascular hemolytic transfusion reactions (potentially fatal), while Rh(D) incompatibility causes hemolytic disease of the fetus/newborn and delayed hemolytic reactions.

Laboratory Science Practice Test

Laboratory Science Practice Test

Laboratory Science Immunology and Serology