Blood typing

Alternative names:

ABO blood typing; cross matching; Rh typing

Normal values:

• Forward typing:
  • If your blood clots when it is mixed with anti-A serum, then you have type A blood.
  • If your blood clots when mixed with anti-B serum, then you have type B blood.
  • If your blood clots when it is mixed with both anti-A and anti-B serums, then you have type AB blood.
  • If your blood does not clot in the presence of either serum, then you have type O blood.
  • If your blood clots when mixed with anti-Rh serum, then you have type Rh-positive blood.
  • If your blood does not clot when mixed with anti-Rh serum, then you have type Rh-negative blood.

• Reverse typing:
  • Clotting that occurs when B cells are mixed with your serum indicates you have type A blood.
  • Clotting that occurs when A cells are mixed with your serum indicates you have type B blood.
  • Clotting that occurs when your serum is mixed with both types of cells indicates you have type O blood.
  • Lack of clotting when your serum is mixed with both types of blood indicates you have type AB blood.

• Transfusions:
  • If you have type A blood, you can receive blood transfusions from people with types A and O blood.
  • If you have type B blood, you can receive blood transfusions from people with types B and O blood.
  • If you have type AB blood, you can receive blood transfusions from people with types A, B, AB, and O blood.
  • If you have type O blood, you can receive blood transfusions from people with type O blood only.
  • If you have Rh-positive blood then you can receive transfusions from people with types Rh-positive and Rh-negative blood.
  • If you have Rh-negative blood then you can receive transfusions from people with type Rh-negative blood only.

Note: Notify your health care provider if you have had past transfusion reactions and any recent administration of blood products, IV contrast, or dextran.

What abnormal results mean:

There are no abnormal values.