Quiz2Know

Human body

Blood Types and Compatibility

Challenge your understanding of ABO groups, Rh factors, antigens, antibodies, and safe transfusion practices.

This is a free, 10-question multiple-choice quiz. Answer each question to see whether you got it right, with an explanation for every answer. There is no sign-up and no time limit — take it as many times as you like, and scroll down for the full answer key once you are done.

Question 1 of 10

0 correct

Which blood type is considered the universal red blood cell donor?

Press A–D to choose · Enter to submit

Answer key & explanations

Every question in this quiz, with the correct answer marked and an explanation of why it is right. Use it to revise before or after taking the quiz above.

  1. 1.Which blood type is considered the universal red blood cell donor?

    • AO positive
    • BO negative✓ Correct
    • CAB positive
    • DAB negative

    Correct answer: O negative

    O-negative red blood cells lack A, B, and Rh antigens, meaning recipient immune systems will not produce antibodies against them.

  2. 2.Which blood group is known as the universal recipient for red blood cell transfusions?

    • AO negative
    • BA positive
    • CB negative
    • DAB positive✓ Correct

    Correct answer: AB positive

    AB-positive individuals express A, B, and Rh antigens, meaning their plasma does not naturally contain antibodies against any of those surface markers.

  3. 3.What type of antibodies are naturally present in the blood plasma of an individual with type A blood?

    • AAnti-A antibodies
    • BAnti-B antibodies✓ Correct
    • CBoth anti-A and anti-B antibodies
    • DNo ABO antibodies

    Correct answer: Anti-B antibodies

    A person with type A blood produces anti-B antibodies to recognize and target foreign type B surface antigens.

  4. 4.What antigens are found on the surface of erythrocytes in a person with type O blood?

    • ABoth A and B antigens
    • BOnly A antigens
    • COnly B antigens
    • DNeither A nor B antigens✓ Correct

    Correct answer: Neither A nor B antigens

    Type O erythrocytes carry neither the A nor B carbohydrate antigen on their cell membranes, though they maintain the underlying H antigen precursor.

  5. 5.The positive or negative designation in human blood typing refers to which antigen?

    • AD antigen (Rh system)✓ Correct
    • BKell antigen
    • CDuffy antigen
    • DMN antigen

    Correct answer: D antigen (Rh system)

    The Rhesus designation is based on the RhD antigen; individuals who have this protein are Rh-positive, while those lacking it are Rh-negative.

  6. 6.Which blood type serves as the universal donor for blood plasma transfusions?

    • AO negative
    • BO positive
    • CAB positive✓ Correct
    • DAB negative

    Correct answer: AB positive

    Because type AB plasma contains neither anti-A nor anti-B antibodies, it can be safely infused into recipients of any ABO group.

  7. 7.What condition can develop when an Rh-negative mother carries an Rh-positive fetus during a second pregnancy?

    • ASickle cell crisis
    • BHemolytic disease of the newborn✓ Correct
    • CAplastic anemia
    • DPolycythemia vera

    Correct answer: Hemolytic disease of the newborn

    Maternal anti-Rh antibodies formed during a previous exposure can cross the placenta and destroy the red blood cells of an Rh-positive fetus.

  8. 8.If two parents both have blood type O, what possible ABO blood types can their biological children inherit?

    • AOnly type O✓ Correct
    • BType O or type A
    • CType O, A, or B
    • DAny ABO blood type

    Correct answer: Only type O

    Type O is an autosomal recessive trait requiring two non-functional alleles, meaning two type O parents can pass on only O alleles to their offspring.

  9. 9.What physical reaction occurs when incompatible blood types are mixed during a transfusion?

    • AHemodilution
    • BAgglutination✓ Correct
    • CEmbolization
    • DFibrinolysis

    Correct answer: Agglutination

    Recipient antibodies bind to foreign antigens on donor erythrocytes, causing the cells to clump together (agglutinate) and lyse.

  10. 10.On which human chromosome is the ABO blood group gene located?

    • AChromosome 1
    • BChromosome 9✓ Correct
    • CChromosome 19
    • DChromosome 23

    Correct answer: Chromosome 9

    The ABO gene is mapped to the long arm of chromosome 9 (9q34.2), encoding glycosyltransferase enzymes that attach sugars to cell surfaces.

More free quizzes