<unk>  is conducted in a medical laboratory to identify potential incompatibilities between<unk>  types in<unk>  transfusion. It is also used to diagnose and prevent some complications of pregnancy that can occur when the baby has a different<unk>  group from the mother.<unk>  includes<unk>  typing, which detects the antigens on red<unk>  cells that determine a person's<unk>  type; testing for unexpected antibodies against<unk>  group antigens (antibody screening and identification); and, in the case of<unk>  transfusions, mixing the recipient's plasma with the donor's red<unk>  cells to detect incompatibilities (crossmatching). Routine<unk>  typing involves determining the ABO and RhD (Rh factor) type, and involves both identification of ABO antigens on red<unk>  cells (forward grouping) and identification of ABO antibodies in the plasma (reverse grouping). Other<unk>  group antigens may be tested for in specific clinical situations.<unk>  makes use of reactions between<unk>  group antigens and antibodies—specifically the ability of antibodies to cause red<unk>  cells to clump together when they bind to antigens on the cell surface, a phenomenon called agglutination. Techniques that rely on antigen-antibody reactions are termed serologic methods, and several such methods are available, ranging from manual testing using test tubes or slides to fully automated systems.<unk>  types can also be determined through genetic testing, which is used when conditions that interfere with serologic testing are present or when a high degree of accuracy in antigen identification is required. Several conditions can cause false or inconclusive results in<unk> . When these issues affect ABO typing, they are called ABO discrepancies. ABO discrepancies must be investigated and resolved before the person's<unk>  type is reported. Other sources of error include the "weak D" phenomenon, in which people who are positive for the RhD antigen show weak or negative reactions when tested for RhD, and the presence of immunoglobulin G antibodies on red<unk>  cells, which can interfere with antibody screening, crossmatching, and typing for some<unk>  group antigens.
Blood compatibility testing
Hematology analyzer
Calibrated automated thrombogram
Blood smear
Drug test
Viral disease testing
Iron tests
Clinical chemistry