The main purpose of testing prior to transfusion is to provide the most compatible blood to the patient in order to minimize the risk of hemolytic transfusion reactions. The type and screen are the first two tests required as pre-transfusion testing. As the name suggests, these are two tests: “type”- to detect the ABO and Rh type of the patient’s red blood cells and “screen” – to detect the presence of antibody(ies) against RBC antigen(s). Antibody/antigen complex formation is thermal range dependent. Antibodies against RBC antigens are optimally reactive at either warm (at or above body temperature) or cold (below body temperature) thermal amplitudes. Warm antibodies are usually acquired and of IgG type. They react at or above 37C. Cold antibodies are usually naturally occurring and of IgM type. They react below 37C.
What is red cell phenotype?
The phenotype of RBCs (RBC phenotyping) refers to determining the type of antigens present on the RBC. The ABO/Rh type in the 'type and screen' is performed on all patients requiring transfusions. However, an extended antigen phenotype may also be performed.
What is phenotype in blood type?
The “phenotype” of any blood group refers to which antigens are detectable on the RBC, and it usually (though not always) corresponds to the genes that the patient carries. Phenotyping is used in blood banking in four main settings: For blood donors, to determine compatibility for a patient with an alloantibody.
What are the two most common blood phenotypes?
Group B (37.39%) was the most common, followed by group O (31.85%). R1R1 and rr were the most common phenotypes amongst Rh positive and Rh negative groups, respectively. A rare phenotype R2Rz was found in one donor.
