CSMLS CSMLS Immunology and Serology 2 — Questions and Answers
Question 1: In a direct Coombs (DAT) test, a positive result indicates:
- Free antibodies in serum
- Antibodies or complement bound to red blood cells in vivo (Correct answer)
- ABO incompatibility in vitro
- Platelet antibodies present
Correct answer: Antibodies or complement bound to red blood cells in vivo
A positive direct antiglobulin test (DAT) indicates that antibodies or complement proteins are already coating the patient's red blood cells in vivo.
Question 2: Rheumatoid factor (RF) is an autoantibody directed against:
- Nuclear antigens
- The Fc portion of IgG (Correct answer)
- Double-stranded DNA
- Platelet glycoproteins
Correct answer: The Fc portion of IgG
Rheumatoid factor is an autoantibody, typically IgM, that targets the Fc region of IgG immunoglobulins.
Question 3: Which antinuclear antibody (ANA) pattern is most associated with systemic lupus erythematosus (SLE)?
- Speckled
- Homogeneous (diffuse) (Correct answer)
- Nucleolar
- Centromere
Correct answer: Homogeneous (diffuse)
The homogeneous (diffuse) ANA pattern is most commonly associated with SLE and correlates with anti-dsDNA and anti-histone antibodies.
Question 4: In a latex agglutination test, the latex particles are coated with:
- Patient serum
- Known antigen or antibody specific for the analyte being tested (Correct answer)
- Saline only
- EDTA anticoagulant
Correct answer: Known antigen or antibody specific for the analyte being tested
Latex particles are coated with a known antigen or antibody so they agglutinate visibly when the complementary analyte is present in the patient sample.
Question 5: The VDRL and RPR tests are used to screen for:
- Hepatitis B
- Syphilis (Correct answer)
- HIV
- Rubella
Correct answer: Syphilis
The VDRL (Venereal Disease Research Laboratory) and RPR (Rapid Plasma Reagin) are non-treponemal screening tests for syphilis.
Question 6: Which cell type is the primary producer of antibodies?
- T lymphocyte
- Plasma cell (Correct answer)
- Natural killer cell
- Macrophage
Correct answer: Plasma cell
Plasma cells are terminally differentiated B lymphocytes that are the primary producers of antibodies (immunoglobulins).
CSMLS CSMLS Immunology and Serology 2
In a direct Coombs (DAT) test, a positive result indicates: