What type of serological testing is primarily used in blood banks to determine a patient's blood group?

Phenotyping is the primary type of serological testing used in blood banks to determine a patient's blood group. This process involves testing the blood sample against known antibodies to observe whether agglutination occurs, which indicates the presence of specific antigens on the surface of red blood cells. By identifying these antigens, blood banks can accurately classify a person's blood type according to the ABO and Rh blood group systems.

While genotyping, which involves analyzing DNA to determine genetic markers, can also be used for blood group determination, it is not typically the primary method employed in blood banks for routine blood type testing. Polymerase chain reaction (PCR) is similarly utilized for genetic analysis but is more specialized and less common in standard blood typing scenarios. The focus in blood banks is largely on immediate and practical serological methods that reliably provide information on blood type, making phenotyping the preferred approach.