Diagnostic Criteria for AIHA
Autoimmune hemolytic anemia (AIHA) is a condition in which the body's immune system mistakenly attacks and destroys its own red blood cells. In order to diagnose AIHA, a doctor will typically perform a blood test to measure the levels of red blood cells, hemoglobin, and hematocrit. Additional tests may also be used to determine the presence of antibodies that could be causing the destruction of red blood cells.
Hemoglobin and Hematocrit Levels
Low levels of hemoglobin and hematocrit are indicative of AIHA. Hemoglobin is the main component of red blood cells that carries oxygen throughout the body. Hematocrit is the measure of the ratio of red blood cells to plasma in the blood.
Reticulocyte Counts
Reticulocytes are immature red blood cells that are produced in the bone marrow before entering the bloodstream. An increase in reticulocytes indicates that the body is trying to increase the production of red blood cells to compensate for those that have been destroyed.
Direct and Indirect Antibody Tests
Direct and indirect antibody tests are used to detect the presence of antibodies that attack the red blood cells. In a direct antibody test, a sample of the patient's serum is mixed with red blood cells. If antibodies are present, the red blood cells will be destroyed. In an indirect antibody test, a sample of the patient's serum is mixed with red blood cells from a healthy donor. If antibodies are present in the patient's serum, the healthy donor cells will be destroyed.
Other Tests
Additional tests may be used to diagnose AIHA. These include a peripheral blood smear, which is used to examine red blood cells for signs of destruction, and a Coombs test, which is used to detect antibodies on the surface of red blood cells.
