Chapter 17a

Overview of Blood Groups

  • Blood groups are classified based on the presence or absence of specific antigens on red blood cells.

  • Understanding blood groups is crucial for safe blood transfusions to prevent transfusion reactions.

ABO Blood Group System

  • Types of Blood Groups:

    • Type A: Has A antigens, produces anti-B antibodies.

    • Type B: Has B antigens, produces anti-A antibodies.

    • Type AB: Has both A and B antigens, does not produce anti-A or anti-B antibodies.

    • Type O: No A or B antigens, produces both anti-A and anti-B antibodies.

Transfusion Reactions

  • Definition: A transfusion reaction occurs when antibodies from one blood group interact with antigens from another blood group.

  • Example:

    • If a type B individual receives type A blood, their anti-A antibodies will attack the A antigens on the donated blood cells, leading to a transfusion reaction.

  • Consequences:

    • Binding of antibodies to incompatible antigens results in agglutination, clogging small blood vessels and impairing gas exchange in tissues.

    • Transfusion reactions can be life-threatening and may result in severe complications or death.

Blood Group Compatibility

  • Type O Blood:

    • Universal donor; can donate to all blood types.

  • Type AB Blood:

    • Universal recipient; can receive blood from all types.

  • Important Note: It is critical to match donors and recipients properly to prevent adverse reactions.

Rh Blood Group System

  • The Rh factor refers to another blood group classification based on the presence of the Rh antigen (also called D antigen on red blood cells).

  • Discovered in Rhesus monkeys, hence the name.

  • The Rh status can be positive (Rh+) if the antigen is present and negative (Rh-) if absent.