Final answer:
A positive auto control is likely if a patient has rouleaux or cold agglutinins since both can cause red blood cells to agglutinate, leading to the positive result in the control test.
Step-by-step explanation:
If a patient has rouleaux or a cold agglutinin, the result of the auto control would likely be a positive auto control. Rouleaux formation refers to a condition where red blood cells (RBCs) stick together and form stacks, resembling a roll of coins. This can cause false-positive results in agglutination tests because RBCs are already clustering, which can be mistaken for agglutination due to antibodies. Cold agglutinins are a type of IgM antibody that can cause RBCs to agglutinate at lower temperatures. The presence of these antibodies would lead to agglutination when patient sample undergoes an auto control test, indicating a positive result. An auto control is included in certain blood tests, such as cross-match assays, to ensure the patient's own serum is not reactive with their RBCs (an indication of autoimmunity), which would interfere with accurate test results.
Rouleaux is a condition where red blood cells stick together in stacks, resembling a roll of coins. This can cause false positive results in the auto control test. Cold agglutinins are antibodies that can cause red blood cells to clump together at low temperatures, leading to a positive auto control result.
The auto control test is performed to ensure the accuracy of a blood typing or cross-match assay. A positive auto control means that the test is functioning properly.