Coombs Test: About Your Child's Test

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What is it?

A Coombs test is a type of antibody test. It checks your child's blood for certain antibodies that attack red blood cells. Antibodies are proteins. They're made by the immune system. Normally, antibodies destroy foreign substances, such as bacteria and viruses.

Why is this test done?

This test is used to check for antibodies:

  • In a newborn baby with jaundice.
  • In a newborn with Rh-positive blood whose mother has Rh-negative blood.
  • In blood before a transfusion.
  • Caused by disease or a blood transfusion.

How do you prepare for the test?

In general, you don't need to prepare before your child has this test. The doctor may give you some specific instructions.

How is the test done?

A health professional uses a needle to take a blood sample, usually from the arm.

How long does the test take?

The test will take a few minutes.

Follow-up care is a key part of your child's treatment and safety. Be sure to make and go to all appointments, and call your doctor if your child is having problems. Ask your doctor when you can expect to have your child's test results.

Where can you learn more?

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The Health Encyclopedia contains general health information. Not all treatments or services described are covered benefits for Kaiser Permanente members or offered as services by Kaiser Permanente. For a list of covered benefits, please refer to your Evidence of Coverage or Summary Plan Description. For recommended treatments, please consult with your health care provider.