Coombs test, also known as anti-human globulin test. It is the most commonly used test to check for autoimmune hemolytic anemia and is divided into direct measurement method and indirect measurement method. A positive direct measurement test indicates the presence of incomplete antibodies on the surface of the patient’s red blood cells; a positive indirect test indicates the presence of incomplete antibodies in the patient’s serum. Positive direct anti-human globulin test is commonly seen in neonatal hemolysis, autoimmune hemolytic anemia, systemic lupus erythematosus, rheumatoid arthritis, malignant lymphoma, and hemolytic reactions caused by drug allergies such as methyldopa and penicillin. Positive indirect test is commonly seen in Rh or ABO gestational immune neonatal hemolytic anemia.