verityyppien

Verityyppien refers to the categorization of human blood based on the presence or absence of specific antigens on red blood cells. In Finnish usage, verityyppien is the genitive plural form of verityyppi, used to refer to blood types. The most clinically important systems are ABO and Rh(D). The ABO system classifies blood into types A, B, AB, and O, determined by the presence of A and/or B antigens and by corresponding antibodies in the plasma. The Rh system denotes the D antigen; individuals are Rh-positive if they have the D antigen and Rh-negative if not. Together, ABO and Rh determine transfusion compatibility, with type O negative commonly used as a universal donor for emergencies and AB positive often regarded as a universal recipient in many contexts.

In addition to ABO and Rh, dozens of other antigen systems influence compatibility and pregnancy outcomes, including Kell, Duffy, Kidd, and MNS. Genetically, the ABO antigen is controlled by the ABO gene on chromosome 9 with alleles IA, IB, and i; the expression is influenced by the H antigen, and the Bombay phenotype arises when the H antigen is absent, mimicking type O serology. The Rh phenotype is primarily determined by the presence of the RHD gene product, though some individuals carry variants such as partial D or DEL alleles.

Typing methods include serological assays and molecular genotyping. Verityyppien knowledge is essential in transfusion medicine, obstetrics, and forensic science. The concept has evolved since the early 20th century, beginning with Landsteiner’s discovery of ABO and later the recognition of the Rh factor, shaping modern blood banking practice.