Blood Groups and Transfusion Practice Questions
20 free Blood Groups and Transfusion practice questions for the Physiology. Tap an option to answer — you get instant feedback, the correct answer, and a detailed explanation for every question.
Which specific antigen is present on the red blood cell membrane of an individual with blood group O?
- A Antigen A
- B Antigen B
- C Both Antigen A and B
- D Neither A nor B
Correct answer: Neither A nor B
Individuals with blood group O lack both A and B surface antigens on their erythrocytes. However, they do possess the H antigen, which is the precursor molecule for A and B antigens.
A person with blood type B positive (B+) will naturally have which antibodies in their plasma?
- A Anti-A and Anti-Rh
- B Only Anti-B
- C Anti-B and Anti-Rh
- D Only Anti-A
Correct answer: Only Anti-A
According to Landsteiner's Law, a person produces antibodies against the ABO antigens they lack. Since this person has B and Rh antigens, they only produce antibodies against the A antigen.
Which blood type is considered the 'Universal Donor' for packed red blood cell transfusions?
- A AB positive
- B AB negative
- C O positive
- D O negative
Correct answer: O negative
Type O negative blood lacks A, B, and Rh antigens on the red cell surface. This means it can be administered to recipients of any blood type with the lowest risk of an immediate hemolytic reaction.
The Rh blood group system is primarily determined by the presence or absence of which protein?
- A Antigen C
- B Antigen E
- C Antigen d
- D Antigen D
Correct answer: Antigen D
While there are many Rh antigens, the 'D' antigen is the most immunogenic. A person is classified as Rh-positive if the D antigen is present on their red blood cells.
In the context of blood groups, what is the 'Bombay Phenotype'?
- A A lack of the H antigen on red blood cells
- B Presence of both A and B antigens but no Rh
- C A mutation causing excessive Rh antigen production
- D The presence of fetal hemoglobin in adults
Correct answer: A lack of the H antigen on red blood cells
Individuals with the Bombay phenotype (hh) cannot produce the H substance, which is necessary to form A or B antigens. Consequently, they appear to be type O but produce potent anti-H antibodies, making them incompatible with normal type O blood.
Erythroblastosis fetalis (Hemolytic Disease of the Newborn) most commonly occurs in which scenario?
- A Rh- mother with an Rh+ fetus
- B Rh+ mother with an Rh- fetus
- C Type A mother with a Type O fetus
- D Type AB mother with a Type B fetus
Correct answer: Rh- mother with an Rh+ fetus
If an Rh-negative mother is sensitized to Rh-positive blood (usually during a previous pregnancy), her anti-D IgG antibodies can cross the placenta. These antibodies then attack and destroy the red blood cells of an Rh-positive fetus.
Which type of immunoglobulin are the naturally occurring anti-A and anti-B antibodies?
- A IgG
- B IgA
- C IgM
- D IgE
Correct answer: IgM
ABO antibodies are primarily IgM, which are large pentameric molecules that do not cross the placenta. In contrast, Rh antibodies (anti-D) are typically IgG and can cross the placental barrier.
Which blood type is considered the 'Universal Recipient' for plasma transfusions?
- A O negative
- B O positive
- C AB negative
- D AB positive
Correct answer: O negative
In plasma transfusions, the 'Universal Donor' and 'Recipient' rules are reversed. Type O individuals are the universal plasma recipients because their red cells have no antigens, meaning they can receive plasma containing any antibodies.
What is the primary purpose of 'cross-matching' before a blood transfusion?
- A To check the exact hemoglobin level of the blood donor's cells
- B To ensure the blood donor has no infectious diseases present
- C To detect agglutination between donor cells and recipient serum
- D To specifically determine only the Rh status of the blood donor
Correct answer: To detect agglutination between donor cells and recipient serum
Cross-matching involves mixing the donor's red cells with the recipient's serum (major cross-match). If agglutination or hemolysis occurs, the blood is incompatible, indicating the presence of antibodies against the donor's cells.
Agglutination in a blood typing test with Anti-A serum and no reaction with Anti-B serum indicates which blood group?
- A Group A
- B Group B
- C Group AB
- D Group O
Correct answer: Group A
Agglutination occurs when the added antibody finds its corresponding antigen. Reaction with Anti-A means Antigen A is present; no reaction with Anti-B means Antigen B is absent, identifying the blood as Group A.
Why is the first Rh-incompatible pregnancy usually not affected by Erythroblastosis fetalis?
- A The mother has not yet produced sufficient anti-D antibodies
- B Fetal Rh antigens are not developed yet
- C The placenta blocks all antibodies during the first pregnancy
- D The fetus produces protective antigens
Correct answer: The mother has not yet produced sufficient anti-D antibodies
Sensitization usually occurs at delivery when fetal and maternal blood mix. It takes time for the mother to develop a significant immune response (anti-D antibodies), so the first Rh+ child is typically born before antibody levels are dangerous.
A person with genotype 'AO' and 'Dd' will have which phenotype?
- A A negative
- B O positive
- C AB positive
- D A positive
Correct answer: A positive
In the ABO system, A is dominant over O, so the blood type is A. In the Rh system, the presence of the D allele (D is dominant over d) makes the person Rh-positive.
Which blood component is most likely to cause a 'Febrile Non-Hemolytic Transfusion Reaction'?
- A Erythrocytes
- B Plasma proteins
- C Platelets
- D Leukocytes
Correct answer: Leukocytes
Febrile reactions are often caused by cytokines released from donor white blood cells or by recipient antibodies reacting against donor HLA antigens on leukocytes. Leukoreduction (filtering out WBCs) significantly reduces this risk.
An individual with blood group AB positive can safely donate red blood cells to which of the following?
- A Anyone (Universal Donor)
- B Only AB positive individuals
- C AB positive and AB negative individuals
- D A positive and B positive individuals
Correct answer: Only AB positive individuals
Type AB positive blood contains A, B, and Rh antigens. It can only be given to other AB positive recipients because any other group would have antibodies (Anti-A, Anti-B, or Anti-D) that would attack the donor cells.
What is the biochemical nature of the A and B blood group antigens?
- A Complex membrane-bound proteins
- B Oligosaccharides (Carbohydrates)
- C Structural membrane phospholipids
- D Long-chain nucleic acid polymers
Correct answer: Oligosaccharides (Carbohydrates)
The ABO antigens are complex sugar chains attached to lipids or proteins on the cell surface. Specific glycosyltransferase enzymes add terminal sugars (N-acetylgalactosamine for A, Galactose for B) to the H substance.
Which clinical emergency is the most severe consequence of an ABO-incompatible transfusion?
- A Delayed hemolytic transfusion reaction (DHTR)
- B Acute Hemolytic Transfusion Reaction (AHTR)
- C Iron overload from multiple repeated transfusions
- D Mild allergic urticarial skin rash reaction
Correct answer: Acute Hemolytic Transfusion Reaction (AHTR)
AHTR occurs when recipient antibodies cause massive, immediate intravascular hemolysis of donor cells. This can lead to disseminated intravascular coagulation (DIC), acute renal failure, and shock.
The inheritance of ABO blood groups is an example of which genetic principle?
- A Incomplete dominance
- B Polygenic inheritance
- C Codominant inheritance
- D Sex-linked inheritance
Correct answer: Codominant inheritance
The A and B alleles are codominant, meaning if both are inherited (genotype AB), both antigens are expressed equally on the cell surface. Both are dominant over the O allele.
Which medication is administered to Rh-negative mothers to prevent Rh sensitization?
- A Warfarin anticoagulant therapy
- B Rho(D) Immune Globulin (RhoGAM)
- C Erythropoietin replacement therapy
- D Cyclosporine immunosuppression
Correct answer: Rho(D) Immune Globulin (RhoGAM)
RhoGAM consists of anti-D antibodies that destroy any fetal Rh+ red cells in the maternal circulation before the mother's immune system can recognize them and start producing its own permanent antibodies.
If a father is blood group O and the mother is blood group AB, what are the possible blood groups of their children?
- A A or B
- B AB or O
- C A, B, or AB
- D Only O
Correct answer: A or B
The father provides an 'O' allele. The mother can provide either an 'A' or a 'B' allele. The resulting genotypes are AO (Type A) or BO (Type B).
Which antigen-antibody reaction is the basis for the direct Coombs test?
- A Detection of unbound free antibodies circulating in serum
- B Detection of antibodies already bound to the surface of RBCs
- C Determination of the patient's complete ABO and Rh blood group
- D Measurement of total serum complement protein levels
Correct answer: Detection of antibodies already bound to the surface of RBCs
The Direct Antiglobulin Test (Coombs test) identifies antibodies (like IgG) or complement proteins that are already attached to the patient's red blood cells in vivo. It is used to diagnose autoimmune hemolytic anemia and hemolytic disease of the newborn.