Blood typing

Blood typing is a laboratory test that identifies blood groups. It is used in transfusion medicine to ensure that patients receive compatible blood products and to prevent transfusion reactions.

Overview

Blood typing is based on the presence or absence of specific antigens on the surface of red blood cells. There are four main blood groups: A, B, AB, and O, and two Rh factors: positive and negative.

Blood Groups

A Group

People with blood group A have A antigens on their red blood cells and anti-B antibodies in their plasma. They can donate blood to groups A and AB, and receive blood from groups A and O.

B Group

People with blood group B have B antigens and anti-A antibodies. They can donate blood to groups B and AB, and receive blood from groups B and O.

AB Group

People with blood group AB have both A and B antigens and no antibodies. They can donate blood to group AB only, but can receive blood from any group.

O Group

People with blood group O have no antigens and both anti-A and anti-B antibodies. They can donate blood to any group, but can receive blood from group O only.

Rh Factor

The Rh factor is another important antigen in blood typing. People who have this antigen are Rh positive, and those who do not are Rh negative. Rh positive people can receive blood from both Rh positive and Rh negative donors, but Rh negative people can only receive blood from Rh negative donors.

Blood Typing Procedure

Blood typing is performed by mixing a sample of a person's blood with antiserum containing known antibodies. If the blood cells clump together, or agglutinate, it indicates that the person's blood contains the antigens that react with the antibodies in the antiserum.

Importance of Blood Typing

Blood typing is crucial in transfusion medicine to prevent transfusion reactions, which can occur if a patient receives incompatible blood. It is also important in pregnancy to prevent hemolytic disease of the newborn, which can occur if an Rh negative mother carries an Rh positive fetus.