Veriryhmämäärityksellä

Veriryhmämääritys, known in English as blood typing or blood group determination, is a method used to classify a person's blood based on the presence or absence of certain inherited antigens on the surface of red blood cells. The most common and clinically significant blood group system is the ABO system, which identifies four main blood types: A, B, AB, and O. These types are determined by the presence of A antigens, B antigens, both A and B antigens, or neither antigen on the red blood cells, respectively. Another crucial system is the Rh factor, which determines whether a person is Rh-positive (RhD antigen present) or Rh-negative (RhD antigen absent).

The principle behind blood typing involves mixing a sample of a person's red blood cells with antibodies that specifically react to the A and B antigens, as well as testing the plasma for antibodies against A and B antigens. Agglutination, or clumping, of the red blood cells indicates the presence of the corresponding antigen. For the Rh factor, red blood cells are tested against an anti-RhD antibody.

Blood typing is essential for safe blood transfusions. Transfusing incompatible blood types can lead to a severe, potentially fatal, immune reaction where the recipient's antibodies attack the transfused red blood cells. Individuals with type O-negative blood are considered universal red blood cell donors because their red blood cells lack A, B, and RhD antigens, making them compatible with most recipients. Conversely, individuals with type AB-positive blood are universal plasma donors as they lack antibodies to A, B, or RhD antigens in their plasma.

Beyond transfusions, blood typing plays a vital role in prenatal care to prevent hemolytic disease of the newborn, a condition that can occur when an Rh-negative mother carries an Rh-positive baby. It is also used in forensic science for identification purposes and in anthropological studies to understand population genetics.