ASCP Immunohematology (Blood Banking) 1 — Questions and Answers
Question 1: A patient with blood type A positive has which antigens on their red blood cells?
- A antigen only
- B antigen and Rh antigen
- A antigen and Rh (D) antigen (Correct answer)
- A and B antigens
Correct answer: A antigen and Rh (D) antigen
Blood type A positive means the RBCs carry the A antigen (ABO) and the D antigen (Rh system).
Question 2: What antibodies does a type O negative individual have in their serum?
- Anti-A only
- Anti-B only
- Anti-A, anti-B, and anti-D (Correct answer)
- No ABO antibodies
Correct answer: Anti-A, anti-B, and anti-D
Type O individuals have both anti-A and anti-B; Rh-negative individuals may have or form anti-D, so O negative serum contains all three.
Question 3: The direct antiglobulin test (DAT) detects:
- Free antibody in serum
- Antibody or complement bound to patient's RBCs in vivo (Correct answer)
- ABO incompatibility in vitro
- Platelet antibodies
Correct answer: Antibody or complement bound to patient's RBCs in vivo
The DAT uses antihuman globulin to detect IgG or complement already coating the patient's red blood cells.
Question 4: Which blood component contains the highest concentration of clotting factors including fibrinogen?
- Packed red blood cells
- Platelet concentrate
- Fresh frozen plasma (FFP) (Correct answer)
- Cryoprecipitate
Correct answer: Fresh frozen plasma (FFP)
Fresh frozen plasma contains all coagulation factors at near-normal concentrations and is used for multiple factor deficiencies.
Question 5: Hemolytic disease of the fetus and newborn (HDFN) most commonly involves which antibody?
- Anti-A (IgM)
- Anti-B (IgM)
- Anti-D (IgG) (Correct answer)
- Anti-Lewis a (IgM)
Correct answer: Anti-D (IgG)
Anti-D is IgG and crosses the placenta; Rh-negative mothers sensitized by Rh-positive fetal cells can develop anti-D causing HDFN.
Question 6: Which crossmatch phase detects most ABO incompatibilities?
- Antiglobulin (Coombs) phase
- 37°C incubation phase
- Immediate spin (IS) phase (Correct answer)
- Room temperature phase only
Correct answer: Immediate spin (IS) phase
ABO antibodies are IgM and react best at room temperature; the immediate spin phase is sufficient to detect most ABO incompatibilities.
ASCP Immunohematology (Blood Banking) 1
A patient with blood type A positive has which antigens on their red blood cells?