Antibody Tests (Coombs Test)

Coombs' Test, Indirect Coombs' Test

Why It Is Done

Direct Coombs test

The direct Coombs test finds antibodies attached to your red blood cells. The antibodies may be those your body made because of disease or those you get in a blood transfusion.

The direct Coombs test also may be done on a newborn baby with Rh-positive blood whose mother has Rh-negative blood. The test shows whether the mother has made antibodies and if the antibodies have moved through the placenta to her baby.

Indirect Coombs test

The indirect Coombs test finds certain antibodies that are in the liquid part of your blood (serum). These antibodies can attack red blood cells but are not attached to your red blood cells. The indirect Coombs test is commonly done to find antibodies in a recipient's or donor's blood before a transfusion.

A test to determine whether a woman has Rh-positive or Rh-negative blood (Rh antibody titer) is done early in pregnancy. If she is Rh-negative, steps can be taken to protect the baby.

Go to previous section	Go to top of page	Go to next section
Author:	Maria G. Essig, MS, ELS	Last Updated: June 12, 2008
Medical Review:	Anne C. Poinier, MD - Internal Medicine W. David Colby IV, MSc, MD, FRCPC - Infectious Disease
© 1995-2010 Healthwise, Incorporated. Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated. This information does not replace the advice of a doctor. Healthwise disclaims any warranty or liability for your use of this information. Your use of this information means that you agree to the Terms of Use. How this information was developed to help you make better health decisions.