B.Sc 1 st year Major 3

Dr. Rinku Sharma 

Blood group and Rh factor 

Blood groups (A, B, AB, O) are determined by specific antigens on red blood cells, while the Rh factor (+ or -) indicates the presence or absence of the Rhesus (D) protein; together they define one of the eight main types, crucial for safe blood transfusions and managing pregnancy risks like hemolytic disease of the newborn. Rh-positive (Rh+) means the protein is present, while Rh-negative (Rh-) means it's absent, with Rh+ being far more common. 

ABO Blood Groups

• • Antigens: Proteins (A or B) on the surface of red blood cells.
  • Antibodies: Natural antibodies in the plasma (e.g., anti-B in Type A blood).
  • Types: A, B, AB, O. 

Rh Factor

• • Definition: An inherited protein (D antigen) on red blood cells.
  • Rh-Positive (Rh+): Has the protein on cells.
  • Rh-Negative (Rh-): Lacks the protein.
  • Genetics: Inherited from parents; Rh+ is dominant, Rh- is recessive. 

Combining ABO & Rh

• • This creates eight main types (e.g., A+, O-, AB+). 
  • Example: A person with Type A+ blood has A antigens and the Rh protein. 

Clinical Significance

• • Transfusions: 

    Receiving incompatible blood can cause severe reactions, so matching ABO and Rh is vital. 
  • Pregnancy: 

    An Rh-negative mother carrying an Rh-positive baby can develop antibodies against the baby's blood, leading to Rh disease (Hemolytic Disease of the Newborn) if not managed with RhoGAM injections.