Coombs test positivity is characteristic of which condition?

Coombs test positivity is characteristic of which condition?

• A. Hemophilia
• B. Autoimmune hemolytic anemia
• C. Sickle cell disease
• D. Iron deficiency anemia

Answer: (B)

Coombs positivity signals that antibodies or complement are bound to red blood cells, which is the hallmark of autoimmune hemolytic anemia. In AIHA, the immune system creates autoantibodies that attach to RBC antigens, causing the cells to be cleared by the spleen and leading to hemolysis. The direct antiglobulin (Coombs) test detects these bound antibodies or complement on the RBC surface, resulting in a positive result. In contrast, hemophilia involves a clotting factor deficiency, not antibody-coated RBCs; sickle cell disease is a hemoglobinopathy without necessary autoantibody coating of RBCs; and iron deficiency anemia is not immune-mediated, so the Coombs test would be negative. Therefore, Coombs positivity is characteristic of autoimmune hemolytic anemia.

Coombs positivity signals that antibodies or complement are bound to red blood cells, which is the hallmark of autoimmune hemolytic anemia. In AIHA, the immune system creates autoantibodies that attach to RBC antigens, causing the cells to be cleared by the spleen and leading to hemolysis. The direct antiglobulin (Coombs) test detects these bound antibodies or complement on the RBC surface, resulting in a positive result. In contrast, hemophilia involves a clotting factor deficiency, not antibody-coated RBCs; sickle cell disease is a hemoglobinopathy without necessary autoantibody coating of RBCs; and iron deficiency anemia is not immune-mediated, so the Coombs test would be negative. Therefore, Coombs positivity is characteristic of autoimmune hemolytic anemia.