Blood Groups/Types

Blood Group Terms

• Antigens: chemical structures imparting specific properties to the surface of the RBC

• Antibodies: protein substance developed in response to foreign body substances

Blood Group Systems

• Detected on the basis of specific reaction with corresponding antibody (either agglutination, lysis, or hemolysis) as a result of the presence or absence of the blood protein antigens on the RBC surface

• Inherited according to Mendelian laws• Fully formed either at birth or in early

postnatal life & persist throughout life

ABO System

• Discovered by Landsteiner in 1900

• Prior to discovery, blood transfusions were hit or miss

• Type A, Type B, Type AB, & Type O

Type A

• 41% of population

• Has A antigens on the RBC surface

• Has anti-B antibodies in the plasma

• Genotypes AA & AO = Phenotype A

Type B

• 10% of population

• Has B antigens on the RBC surface

• Has anti-A antibodies in the plasma

• Genotype BB & BO = Phenotype B

Type AB

• 4 % of population• Has A & B antigens on the RBC

surface• Has NO antibodies in the plasma• Universal Recipient: can receive

Type A, Type B, Type AB, or Type O blood NO antibodies in plasma to react with antigens

• Genotypes: AB = Phenotype AB

Type O

• 45% of population• Has NO antigens on RBC surface• Has anti-A & anti-B antibodies in the

plasma• Universal Donor: can be given to

any blood type no antigens on the RBCs

• Genotype OO = Phenotype O

Rh System

• Discovered by Landsteiner & Wiener in 1937

• Discovered in the Rhesus monkey

• Rh is an antigen on the RBC surface

• Rh + has the antigens on the RBC (85% of population)

• Rh – does NOT have the Rh antigens

• Rh + can accept Rh + or Rh – blood

• Rh – can accept ONLY Rh - blood

Rh Incompatibility

• When Rh– person receives Rh+ blood in a transfusion person develops antibodies against the Rh+ factor

• Clinical problem if second transfusion of Rh+ blood given Rh antibodies will clump with the Rh antigens

• S & S of transfusion reaction: chills, fever, rash, itching, SOB, nausea, nephralgia, hematuria, shock & death

Erythroblastosis fetalis

• Rh– mother and Rh+ father Rh+ child 1st pregnancy

• Mother develops antibodies to baby’s Rh+ antigens

• 2nd pregnancy with Rh+ child mother’s anti-Rh antibodies attack unborn child’s RBCs

• Prevention: shot of Rhogam shortly after birth of first Rh+ baby to block development of antibodies

Erythroblastosis fetalis

• Antigen-antibody reaction due to mixing of Rh+ blood of fetus with Rh- blood of mother during 2nd Rh+ pregnancy

• Prevented with shot of Rhogam at birth of 1st Rh+ baby