Blood Groups and Blood Types

Blood Type

A classification of blood based on the presence or absence of specific inherited antigens on the surface of red blood cells

Antigen

A substance made of glycoproteins or glycolipids that the immune system recognizes as foreign or harmful and uses to trigger an immune response.

Antibody

A protective protein produced by the immune system to neutralize foreign substances called antigens

ABO Blood Group

A classification of human blood based on the presence or absence of two glycolipid antigens called A and B on red blood cells.

Type A Blood

Has A antigen and anti-B antibodies; can receive A and O blood.

Type B Blood

Has B antigen and anti-A antibodies; can receive B and O blood.

Type AB Blood

Has A and B antigens with no antibodies; universal recipient.

Type O Blood

Has no antigens but anti-A and anti-B antibodies; universal donor.

Blood Transfusion

Procedure where donated blood or specific blood components are delivered into the body through a narrow tube placed in a vein

Blood Transfusion: Purpose

A transfusion is most often given to alleviate anemia, to increase blood volume (for example, after a severe hemorrhage), or to improve immunity.

Blood Incompatibility (Agglutination)

Red blood cells clump when antibodies bind to antigens, preventing their movement and spread and making them easier for phagocytes to engulf and destroy.

Blood Incompatibility: Effects

An incompatible or contaminated blood transfusion can cause red blood cell destruction, kidney damage, or infection.

Rh Blood Group

An inherited protein on the surface of red blood cells that determines whether a person’s blood type is positive or negative

Rh Positive

Rh antigen present; can receive Rh+ and Rh− blood.

Rh Negative

No Rh antigen; can receive only Rh− blood

Cross-Match

A vital pre-transfusion test that mixes donor red blood cells with the recipient's serum to check for compatibility and prevent life-threatening reactions