Blood typing (ABO and RhD) is a medical test that identifies the antigens on the surface of red blood cells and determines a person's blood type according to the two main systems: ABO and RhD. This information is crucial for blood transfusions, pregnancy care, and surgical procedures to prevent serious immune reactions.
Blood is divided into different blood types depending on the presence of specific antigens: A, B, AB, or O, and whether the Rh antigen (D antigen) is present (Rh-positive) or absent (Rh-negative). The combination of these systems results in eight blood groups, such as A RhD+ or O RhD-.
The importance of blood grouping
Blood grouping has several important clinical uses, including:
- Blood transfusions: Ensuring compatible blood between donor and recipient to avoid immune reactions.
- Pregnancy care: Identifying Rh incompatibility between mother and fetus to prevent complications such as hemolytic disease of the newborn.
- Surgical procedures: Planning blood supplies to manage potential transfusion needs during surgery.
The ABO system
The ABO system divides blood into four main groups based on antigens:
- Blood group A: Has A antigen and anti-B antibodies.
- Blood type B: Has B antigen and anti-A antibodies.
- Blood type AB: Has both A and B antigens but lacks antibodies.
- Blood type O: Lacks both A and B antigens but has anti-A and anti-B antibodies.
When transfused, the blood types must match to avoid the recipient's antibodies attacking the transfused blood.
The Rh system
The Rh system is based on the presence or absence of the D antigen:
- Rh-positive (RhD+): Has the D antigen.
- Rh-negative (RhD-): Lacks the D antigen.
Rh incompatibility between an Rh-negative mother and an Rh-positive fetus can lead to complications, which can be prevented with anti-D immunoglobulin.
Red blood cell antibody screening
Screening for irregular red blood cell antibodies is an important part of blood grouping. These antibodies can form after blood transfusions or pregnancies and cause complications in future transfusions or pregnancies. The analysis identifies these antibodies and contributes to safer treatment.
How is blood grouping performed?
Blood grouping is performed by analyzing a blood sample. Two main components are analyzed:
- ABO and RhD grouping: Identifies the individual's blood group and Rh status.
- Erythrocyte antibody screening: Detects the presence of irregular antibodies.
The analyses are performed with high precision to ensure accurate and reliable results.
Interpretation of test results
- Normal values: Identifies blood group and shows the absence of irregular antibodies.
- Abnormalities: May indicate the presence of irregular antibodies or the risk of incompatibility during transfusion or pregnancy.
Blood grouping is an important medical analysis that is used to optimize care and treatment in many different contexts. Knowing your blood group contributes to increased safety in both emergency and planned situations.