Which test is performed to determine a patient’s blood group?

The test that determines a patient's blood group is ABO typing, also known as blood typing. This process specifically identifies the blood group based on the presence or absence of certain antigens on the surface of red blood cells. The primary blood groups are A, B, AB, and O, which are defined by the specific antigens that are present.

ABO typing is crucial because it informs healthcare providers about a patient's blood group, which is essential for safe blood transfusions, organ transplants, and understanding potential risks during pregnancy and childbirth. If a patient receives blood from an incompatible group, it can provoke a serious immune reaction.

Blood chemistry tests, on the other hand, evaluate substances in the blood to assess organ function, metabolism, and other health indicators, but they do not identify blood groups. A complete blood count (CBC) is focused on evaluating the components of blood, such as red blood cells, white blood cells, and platelets, rather than categorizing blood groups. The crossmatch test is used before a transfusion to ensure compatibility between donor and recipient blood, but it is performed after the blood group has already been established through ABO typing. Thus, the correct answer reflects the specific test designed explicitly for determining blood groups.