Immunohematology and Transfusion Medicine

maintaining oxygen-carrying capacity

restoring blood volume

replacing coagulation factors

restoring leukocyte functions

benefits/reasons for transfusion

packed red blood cells (RBCs)

irradiated RBC

frozen RBC

fresh frozen plasma

cryoprecipitate

whole blood, blood components, and derivatives for transfusion

anticoagulants

labeling

storage of blood

collection of red blood cells

blood group of label

more prominent

may indicate intended use

may indicate Rh, Kell phenotypes

expiry date of label

expiration date + time shown if other than midnight

special testing/characteristics on label (optional)

red cell phenotype

CMV status

special info, e.g. antibodies present

in eye readable and optionally bar code format

syphilis test

hepatitis test

HIV/AIDS test

Human T-Cell Lymphotropic Virus test

West Nile test

Trypanosoma cruzi test

routine blood screening tests for blood processing

autologous transfusions

blood collected from patient for re-transfusion at later time into the same individual

direct transfusions

transfers blood directly from a donor to a recipient without intermediate storage

commonly used in emergency or battlefield settings

antigen

a foreign (different from self) substance that, when introduced into the body of a person lacking antigen, results in an immune response; formation of a corresponding antibody

antibody

a protein found in plasma that is formed as a result of antigenic stimulation and is specific for an antigen

isoantibodies

“naturally occurring” ABO antibodies

unexpected/immune antibodies

results from specific antigenic stimulation form RBCs

anti-sera

a highly purified solution of antibody and is named based on the antibody it contains

agglutination

clumping of RBCs caused by the reaction of a specific antibody and antigen on the cells

antisera

agglutination

hemolysis

means of detecting antigen-antibody reactions

hemolysis

destruction of RBCs by activation of complement (a reagent used in blood banks)

all samples have to be free of this to be tested

gel technology

traditional tube method

blood banking techniques

positive reaction

well coated with red cell stroma + serum containing antibodies —> antibody in serum bound to red cell stroma + indicator red cells coated with anti-IgM —> indicator red cells bound to antibodies —> _____________

negative reaction

well coated with red cell stroma + serum containing no antibodies + indicator red cells coated with IgM —> antibodies and therefore indicator red cells not bound —> ________

H antigen

gene product: L-Fucosyltransferase

immunodominant sugar: L-fucose

A antigen

gene product: N-acetylgalactosamine

immunodominant sugar: N-acetylgalactosamine

B antigen

gene product: D-galactosyltransferase

immunodominant sugar: D-Galactose

ABH antigens

ABO red blood cel group system

type A

agglutination with anti-A serum (negative reaction)

no agglutination with anti-B serum (positive reaction)

type B

no agglutination with anti-A serum (positive reaction)

agglutination with anti-B serum (negative reaction)

type AB

agglutination with anti-A and anti-B serum (negatives reactions)

type O

no agglutination with anti-A and anti-B serum (positive reactions)

type A

antigen: A

antibody: anti-B

blood types compatible in an emergency: A, O

type B

antigen: B

antibody: anti-A

blood types compatible in an emergency: B, O

type AB

antigen: A + B

antibody: none

blood types compatible in an emergency: A, B, AB, O

type O

antigen: none

antibody: anti-A + anti-B

blood types compatible in an emergency: O

group O

approximately 45% of the population

no A or B antigens present

these individuals form potent anti-A and anti-B antibodies which circulate in the blood plasma at all times

group A

approximately 40% of the population

no B antigens present

these individuals form potent anti-B antibodies that circulate in the blood plasma at all times

group B

approximately 11% of the population

no A antigens present

these individuals form potent anti-A antibodies that circulate in the blood plasma at all times

group AB

approximately 4% of the population

both A and B antigens present

these individuals possess no ABO antibodies

Rh (D) antigen

a blood group system with many antigens, one is D

refers to the presence or absence of the D antigen on the red blood cell

unlike the ABO group, individuals who lack the D antigen do not naturally make it

agglutination (hemagglutination)

RBCs have antigens that combine with serum antibodies (either patient or reagent)

antibody bridges form with antigens on adjacent cells resulting in agglutination

4+

one large aggregate

3+

a few medium to large aggregates

2+

several medium-sized aggregates

1+

many small aggregates

0

no visible agglutination

front type

testing for the presence of antigens on RBCs using anti-sera and patient cells

type A

anti-A antisera —> positive (3-4+)

anti-B antisera —> negative (0)

type B

anti-A antisera —> 0

anti-B antisera —> positive (3-4+)

type O

anti-A antisera —> 0

anti-B antisera —> 0

type AB

anti-A antisera —> positive (3-4+)

anti-B antisera —> positive (3-4+)

back type

testing for the presence of antibodies in plasma using reverse group cells and patient plasma

type A

reagent A cells —> 0

reagent B cells —> 3-4+ (positive)

type B

reagent A cells —> 3-4+ (positive)

reagent B cells —> 0

type O

reagent A cells —> 3-4+

reagent B cells —> 3-4+

type AB

reagent A cells —> 0

reagent B cells —> 0

Rh positive

presence of D antigen

Rh negative

absence of D antigen

positive

anti-D antisera —> 3-4+

negative

anti-D antisera —> 0

type O

45% of blood type

type A

40% of blood type

type B

11% of blood type

type AB

4% of blood type