What does ABO reverse typing utilize to determine blood type?

ABO reverse typing is a crucial step in blood typing, primarily used to verify a patient's ABO blood type. This process involves mixing a patient's serum with known group A and group B red blood cells (often referred to as A1 and B cells).

In this test, if the patient’s serum contains antibodies against certain blood group antigens, such as anti-A or anti-B, these antibodies will react with the corresponding antigens on the known red blood cells. This reaction leads to agglutination, confirming the presence of those specific antibodies and, consequently, identifying the patient’s ABO blood group.

Specifically, in the context of reverse typing, if a patient is group A, their serum will contain anti-B antibodies that will agglutinate with group B red blood cells. Conversely, if the serum is group B, it will contain anti-A antibodies that will agglutinate with group A cells. This relationship allows for accurate determination of the blood group.

Therefore, the correct answer highlights the use of the patient's serum in conjunction with known A1 and B cells to establish a definitive blood type. Understanding this methodology is essential for ensuring safe blood transfusions and for the overall management of patients requiring blood products.