Use of genomics for decision‐making in transfusion medicine: laboratory practice

Blood group antigens are classically tested through haemagglutination techniques, which show limitations that may be overcome by genomics. Numerous techniques are available for RBC genotyping, including high‐throughput devices based on microarray DNA‐chips or mass spectrometry technologies. This article aims to give an overview of the major indications of molecular testing in the immunohaematology reference laboratory, which can be summarized as follows: blood typing in recently transfused patients; prediction of blood types in patients and donors when antisera are in short supply or unavailable; blood typing in patients with a positive direct antiglobulin test; manufacturing of RBC antibody identification panels; detection of weakly expressed RBC antigens in blood donors; distinction between auto and alloantibodies; investigation of blood type discrepancies; mass screening for rare donors. Despite the limitations of DNA analysis under certain circumstances, genomics has now become a routine and essential adjunct tool to complex serological case solving in most immunohaematology reference laboratories, and is now fully considered part of the decision‐making process in transfusion medicine.