What test is used to diagnose autoimmune hemolytic anemia?

What test is used to diagnose autoimmune hemolytic anemia?

• A. Red cell fragility test
• B. Modified knott
• C. Coombs
• D. Coggins

Answer: (C)

Autoimmune hemolytic anemia is caused by antibodies that bind to a person’s own red blood cells, leading to their destruction. The test that detects those antibodies or complement attached to the surface of red blood cells is the Coombs test, specifically the direct antiglobulin test. A positive direct Coombs test shows in vivo coating of red cells with immunoglobulin or complement, which confirms immune-mediated hemolysis consistent with AIHA. The other tests don’t assess antibodies on red cells: the red cell fragility test measures membrane stability and is used for conditions like hereditary spherocytosis; the modified Knott test detects microfilariae in blood; and the Coggins test screens for equine infectious anemia.

Autoimmune hemolytic anemia is caused by antibodies that bind to a person’s own red blood cells, leading to their destruction. The test that detects those antibodies or complement attached to the surface of red blood cells is the Coombs test, specifically the direct antiglobulin test. A positive direct Coombs test shows in vivo coating of red cells with immunoglobulin or complement, which confirms immune-mediated hemolysis consistent with AIHA. The other tests don’t assess antibodies on red cells: the red cell fragility test measures membrane stability and is used for conditions like hereditary spherocytosis; the modified Knott test detects microfilariae in blood; and the Coggins test screens for equine infectious anemia.