Know About Blood Group ABO & Rh Typing-Automated (Blood)
A blood type (also called a blood group) is a classification of blood based on the presence and absence of antibodies and also based on the presence or absence of inherited antigenic substances on the surface of red blood cells. Blood types are based on the markers (specific carbohydrates or proteins) or antigens on the surface of red blood cells (RBCs). Two major antigens or surface identifiers on human RBCs are the A and B antigens. Another important surface antigen is called Rh. Blood typing detects the presence or absence of these antigens to determine a person's ABO blood group and Rh type.
People whose red blood cells have A antigens are in blood group A, those with B antigens are group B, those with both A and B antigens are in group AB, and those who do not have either of these markers are in blood group O.
If the Rh protein is present on the red blood cells, a person's blood type is Rh+ (positive); if it is absent, the person's blood is type Rh- (negative).
Our bodies naturally produce antibodies against the A and B antigens that we do not have on our red blood cells. For example, a person who is blood type A will have anti-B antibodies directed against the B antigens on red blood cells and someone who is type B will have anti-A antibodies directed against the A antigens. People with type AB blood have neither of these antibodies, while those with type O blood have both.
The following table indicates the type of antibodies a person is expected to have based on their blood type.
A PERSON WITH BLOOD TYPE ... WILL HAVE ANTIBODIES TO ...
A B antigen
B A antigen
AB Neither antigen
O A and B antigens
These antibodies are useful for determining a person's blood type and help determine the types of blood that he or she can safely receive (compatibility). If a person who is group A with antibodies directed against the B antigen, for example, were to be transfused with blood that is type B, his or her own antibodies would target and destroy the transfused red blood cells, causing severe, potentially fatal complications. Thus, it is critical to match a person's blood type with the blood that is to be transfused.
Unlike antibodies to A and B antigens, antibodies to Rh are not produced naturally. That is, Rh antibodies develop only after a person who does not have Rh factor on his or her red blood cells (Rh negative) is exposed to Rh positive red blood cells. This can happen during pregnancy or birth when an Rh-negative woman is pregnant with an Rh-positive baby, or sometimes when an Rh-negative person is transfused with Rh-positive blood. In either case, the first exposure to the Rh antigen may not result in a strong response against the Rh positive cells, but subsequent exposures may cause severe reactions.
Blood Group; Rh Factor; ABO Group and Rh Type.
Anti-D Immunoglobulin; Haemolytic Disease Of the Newborn(HDN);
To determine your ABO blood group and Rh type
ABO grouping and Rh typing are performed on all donated blood. They are also performed when people require blood transfusion. Conditions or situations that may warrant a transfusion include:
Severe anemia and conditions causing anemia such as sickle cell disease and thalassemia.
Bleeding during or after surgery.
Injury or trauma.
Excessive blood loss.
Cancer and the effects of chemotherapy.
Bleeding disorders such as hemophilia.
Testing is ordered when a woman becomes pregnant to determine whether she is Rh negative or positive. All newborn babies of Rh-negative mothers are typed for ABO and Rh soon after birth to determine if the mother needs to receive Rh immune globulin.
Blood typing may be ordered when a person becomes a candidate for an organ, tissue, or bone marrow transplant, or when a person wishes to become a donor. It is one of the first of many tests used when determining whether a potential donor and recipient are compatible.
Sometimes blood typing may be done as part of the process for determining whether someone could be a blood relative. For more on this, see the article The Universe of Genetic Testing: The Basics, Identity Testing, and Parentage Testing.