Final answer:
The Coombs test, including both its direct and indirect forms, is the primary diagnostic test for immune hemolytic anemia, detecting antibodies either bound to red blood cells or unbound in the patient's serum.
Step-by-step explanation:
Diagnosing Immune Hemolytic Anemia
The primary test used to diagnose immune hemolytic anemia is the Coombs test. Specifically, the direct Coombs test (DAT) detects antibodies or complement proteins bound directly to the surface of red blood cells in vivo. When a patient presents with symptoms such as jaundice, a blood sample is taken and mixed with Coombs' reagent, which contains antihuman antibodies. This reagent facilitates hemagglutination, helping to reveal if antibodies are attacking the patient's own red blood cells, which can lead to hemolysis and anemia.
There is also the indirect Coombs test (IAT), which looks for unbound antibodies against red blood cell antigens in a patient's serum. The IAT is particularly useful in screening prior to blood transfusions and in pregnant women for antibodies that could potentially cause hemolytic disease of the newborn. Overall, both the direct and indirect Coombs tests are vital for identifying conditions that can cause red blood cells' destruction.