Transfusion Medicine

Question 1

blood antigen vs antibody

Answer 1

antigen is on the blood cell, antibody is in the plasma serum

Question 2

Blood group O

Answer 2

H antigen, anti-A/B antibodies. O-=universal blood cell donor, universal plasma recipient. can only receive O blood.

Question 3

Blood group A

Answer 3

A antigen, anti-B serum antibody. can receive A & O blood/plasma

Question 4

Blood group B

Answer 4

B antigen, anti-A serum antibody. Can receive B & O blood.

Question 5

Blood group AB

Answer 5

A/B antigens, no serum antibodies. AB+=universal blood recipient, universal plasma donor. can only receive AB plasma

Question 6

most common blood type?

Answer 6

O

Question 7

where are ABO antigens located?

Answer 7

on all body tissues. need to be tested before any type of transplant

Question 8

hemolytic disease of the newborn

Answer 8

Rh- mother has a Rh+ baby. At delivery, she gets exposed to Rh+ red cells of baby and begins producing Rh+ antibodies, which can cause anemia, hepato/splenomegaly, brain damage in next Rh+ baby

Question 9

treatment for hemolytic disease of newborn?

Answer 9

Rhogam, a concentrated anti-Rh antibody.

dose Rh- mother at 28 weeks and then again at birth if newborn is Rh+. or at any point of trauma during the pregnancy

Question 10

packed RBC effect

Answer 10

one unit raised Hgb 1-1.5 g/dL

Question 11

platelet infusion effect

Answer 11

one unit raises count 5-10,000

Question 12

crossmatch

Answer 12

the final checkpoint in compatibility testing for transfusions. take cells from donation bag and mix with patients serum to ensure no agglutination occurs

Question 13

top 3 causes of transfusion related fatality

Answer 13

acute hemolytic transfusion run (usually due to clerical error), bacterial contamination of platelets, TRALI (pulmonary edema)

Question 14

hemolytic transfusion rxn of ABO group

Answer 14

ABO antigens induce naturally occurring IgM antibodies to destroy transfused cells by fixing complement and causing intravascular hemolysis

Question 15

Rh antibodies

Answer 15

not naturally occurring. only present if Rh- person has been exposed to the antigen through pregnancy or transfusion.

Question 16

hemolytic transfusion run of Rh(D)

Answer 16

anti-Rh(D) is IgG and destroys transfused RBCs by reticule-endothelial phagocytosis mediated by Fc and complement receptors (extravascular hemolysis)

Question 17

Coombs tests for blood type

Answer 17

Direct for ABO groups. IgM is large enough to bridge two RBCs.
Indirect for Rh(D0. IgG too small to bridge two RBCs, so patients serum is used and RBCs are added

Question 18

hemolytic disease of the newborn caused by IgG to Rh(D)

Answer 18

erythroblastosis fetalis

Question 19

forward typing

Answer 19

test patient’s RBCs for antigen by adding anti-A/B/D.

Question 20

Reverse typing

Answer 20

test patients serum for antibodies. if anti-A is present, will agglutinate with A cells and patient is either B or O

Question 21

antibody screen

Answer 21

tests for alloantibodies to RBC antigens. serum from patient is incubated with screening cells that have known antigens and then run through a medium with antigens. if alloantibodies are present, will not move through medium to bottom

Question 22

direct antiglobulin test (DAT)

Answer 22

Direct Coombs Test. used to detect antibodies that are stuck to the surface of patients red blood cells.

Question 23

indirect coombs test (IAT)

Answer 23

looks for free-flowing antibodies against certain red blood cells. tests patients serum with reagent red cells.

Question 24

which blood type is most common?

Answer 24

O