What is a Coombs test?
There are two forms of the Coombs’ test: direct and indirect. The direct Coombs’ test is used to detect antibodies that are already bound to the surface of red blood cells. Many diseases and drugs (quinidine, methyldopa, and procainamide) can lead to production of these antibodies. These antibodies sometimes destroy red blood cells and cause anemia. This test is sometimes performed to diagnose the cause of anemia or jaundice. The indirect Coombs’ test looks for unbound circulating antibodies against a series of standardized red blood cells. The indirect Coombs’ test is only rarely used to diagnose a medical condition.
