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Coombs test

Also called: Direct antiglobulin test, DAT, Indirect Coombs

The Coombs test looks for antibodies attacking red blood cells. It's used for hemolytic anemia, transfusions, pregnancy, and newborn jaundice.

SampleA small tube of blood from a vein in your arm
Fasting?Usually not needed
ResultsSame day to a few days
Good to knowOne result rarely tells the whole story. Your provider looks at your results together with your symptoms, exam, and other tests.

What the test is

The direct test checks your red cells; the indirect test checks your blood for antibodies.

Why it's done

  • Hemolytic anemia
  • A transfusion reaction
  • Pregnancy antibody screening
  • Jaundice in a newborn

Getting ready and what happens

  • None.

How the test is done

  • A health worker cleans the skin, puts a band around your arm, and draws blood from a vein with a small needle. It takes a few minutes.

What the results mean

Positive

Suggests immune red cell breakdown; the cause is investigated.

Questions to ask your provider

  • What do my results mean for me?
  • Do I need to repeat this test or have other tests?

Risks

A blood draw is very safe. You may have slight pain or a small bruise where the needle went in.

Related conditions

Related tests

Sources

Last updated 2026-11-13.