Final answer:
An autologous control includes a patient's own serum and cells used to ensure that agglutination observed in a test is not due to autoantibodies in the patient’s blood.
Step-by-step explanation:
An autologous control is a component of laboratory testing, particularly in immunohematology, where it's used to help determine how a patient's immune system will react to their own tissues or blood cells during procedures such as transfusions or transplantation. The control is composed of patient's own serum and patient's own cells. This is used to ensure that any agglutination or reactivity observed in a test is due to the presence of foreign antigens and not to some innate abnormality or autoantibody in the patient's own blood.
For example, if a patient is undergoing blood transfusion, and there's a concern for potential antibodies that could react with transfused blood, an autologous control, which includes the patient's serum and cells, helps identify if the serum contains autoantibodies. If the agglutination occurs only when the patient's serum is mixed with donor cells and not with their own cells, it suggests the presence of alloantibodies rather than autoantibodies.