Blood Type Test (ABO Grouping and Rh Typing)
Human blood is divided into four major types A, B, AB and O. This blood blood test that can tell whether a persons blood is any one of these types. The test also indicates whether a persons blood is Rh-negative or Rh-positive. Its important to know your blood type for several reasons. First, if you ever need a blood transfusion, its critical to know which types of blood are compatible with yours. For example:
- People with type A blood can only have transfusions of A and O blood.
- People with type B blood can only have transfusions of B and O blood.
- People with AB blood can take A, B, AB and O blood. Thats why AB blood is called a universal recipient.
- People with type O blood can only have transfusions of O blood. Since every blood type can have a transfusion of O blood, O blood is called a universal donor.
A second reason for needing to know your blood type is an Rh factor might contribute to complications of pregnancy if the mother and fetus have different Rh factors. People with different blood types may be more at risk for certain diseases than the general population. Typically, blood type tests are taken:
- Before pregnancy or at the beginning of pregnancy
- Before you get a transfusion
- Before you donate blood
- Before you have surgery
- To determine whether two people have a blood relationship
ABO grouping and Rh typing
An ABO grouping and Rh typing blood test measures are the antigens on top of the patients red blood cells. Once the blood is drawn, it is mixed with antibodies that attack A and B blood. The blood type is determined by checking to see if the blood cells to stick to each other. Blood cells sticking to each other are an indication that the patients blood reacted to one of the A or B antibodies.
The blood is then back-typed. The serum of the blood is mixed with type A or B blood. If the patient has type A blood, he or she will have antibodies that attack B type blood. People with B blood have antibodies that attack A type blood. Blood that's type O attacks both A and B blood.
Rh factor is determined by seeing if the surface of the blood has the factor. If its present, the patient is Rh positive. If its missing, the person is Rh negative.
Related Laboratory Tests
A Blood Type Test is often ordered with a Pregnancy Test
, as part of a prenatal testing
, or screening prior to marriage.