Red Blood Cell Antibody Screen

What is an RBC Antibody Screen?

An RBC (red blood cell) antibody screen is a blood test that looks for antibodies in your red blood cells.Red blood cell antibodies may cause harm to you after a transfusion or, if you are pregnant, to your baby. An RBC antibody screen can find these antibodies before they cause health problems.

Antibodies are proteins made by your body to attack foreign substances such as viruses and bacteria. Red blood cell antibodies may show up in your blood if you are exposed to red blood cells other than your own. This usually happens after a blood transfusion or during pregnancy, if a mother's blood comes in contact with her unborn baby's blood. Sometimes the immune system acts like these red blood cells are "foreign" and will attack them.

Other names: antibody screen, indirect antiglobulin test, indirect anti-human globulin test, IAT, indirect coombs test, erythrocyte Ab

What is it used for?

RBC screen is used to:

Check your blood before a blood transfusion. The test can show whether your blood is compatible with the donor's blood. If your blood is not compatible, your immune system will attack the transfused blood as if it is a foreign substance. This will be harmful to your health.
Check your blood during pregnancy. The test can show whether a mother's blood is compatible with the blood of her unborn baby. A mother and her baby may have different types of antigens on their red blood cells. Antigens are substances that produce an immune response. Red blood cell antigens include the Kell antigen and the Rh antigen.
- If you have the Rh antigen, you are considered Rh positive. If you don't have the Rh antigen, you are considered Rh negative.
- If you are Rh negative and your unborn baby is Rh positive, your body may begin to make antibodies against your baby's blood. This condition is called Rh incompatibility.
- Both Kell antigens and Rh incompatibility may cause a mother to make antibodies against her baby's blood. The antibodies can destroy the baby's red blood cells, causing a severe form of anemia. But you can get a treatment that will prevent you from making antibodies that could harm your baby.
Check the blood of your unborn baby's father.
- If you are Rh negative, your baby's father may be tested to find out his Rh type. If he is Rh positive, your baby will be at risk for Rh incompatibility. Your health care provider will probably perform more tests to find out whether or not there is incompatibility.

Why do I need an RBC antibody screen?

Your health care provider may order an RBC screen if you are scheduled to get a blood transfusion, or if you are pregnant. An RBC screen is usually done in early pregnancy, as part of routine prenatal testing.

What happens during an RBC antibody screen?

A health care professional will take a blood sample from a vein in your arm, using a small needle. After the needle is inserted, a small amount of blood will be collected into a test tube or vial. You may feel a little sting when the needle goes in or out. This usually takes less than five minutes.

Will I need to do anything to prepare for the test?

You don't need any special preparations for an RBC screen.

Are there any risks to the test?

There is very little risk to having a blood test. You may have slight pain or bruising at the spot where the needle was put in, but most symptoms go away quickly.

What do the results mean?

If you are getting a blood transfusion: The RBC screen will show whether your blood is compatible with the donor's blood. If it is not compatible, another donor will need to be found.

If you are pregnant: The RBC screen will show whether your blood has any antigens that could harm your baby, including whether or not you have Rh incompatibility.

If you have Rh incompatibility, your body may begin to make antibodies against your baby's blood.
These antibodies are not a risk in your first pregnancy, because the baby is usually born before any antibodies are made. But these antibodies could harm your unborn baby in future pregnancies.
Rh incompatibility can be treated with an injection that prevents your body from making antibodies against your baby's red blood cells.
If you are Rh positive, there is no risk of Rh incompatibility.

If you have questions about your results, talk to your health care provider.

Is there anything else I need to know about an RBC antibody screen?

Rh incompatibility is not common. Most people are Rh positive, which does not cause blood incompatibility and poses no health risks.

References

ACOG: The American Congress of Obstetricians and Gynecologists [Internet]. Washington D.C.: American Congress of Obstetricians and Gynecologists; c2017. The Rh Factor: How It Can Affect Your Pregnancy; 2013 Sep [cited 2017 Sep 29]; [about 3 screens]. Available from: https://www.acog.org/Patients/FAQs/The-Rh-Factor-How-It-Can-Affect-Your-Pregnancy#what
American Pregnancy Association [Internet]. Irving (TX): American Pregnancy Association; c2017. Rh Factor [updated 2017 Mar 2; cited 2017 Sep 29]; [about 2 screens]. Available from: http://americanpregnancy.org/pregnancy-complications/rh-factor
American Society of Hematology [Internet]. Washington D.C.: American Society of Hematology; c2017. Hematology Glossary [cited 2017 Sep 29]; [about 3 screens]. Available from: http://www.hematology.org/Patients/Basics/Glossary.aspx
ClinLab Navigator [Internet]. ClinLabNavigator; c2017. Prenatal Immunohematologic Testing [cited 2017 Sep 29]; [about 2 screens]. Available from: http://www.clinlabnavigator.com/prenatal-immunohematologic-testing.html
C.S. Mott Children's Hospital [Internet]. Ann Arbor (MI): The Regents of the University of Michigan; c1995-2017. Coombs Antibody Test (Indirect and Direct); 2016 Oct 14 [cited 2017 Sep 29]; [about 2 screens]. Available from: http://www.mottchildren.org/health-library/hw44015
Lab Tests Online [Internet]. Washington D.C.: American Association for Clinical Chemistry; c2001–2017. Blood Typing: Common Questions [updated 2015 Dec 16; cited 2016 Sep 29]; [about 5 screens]. Available from: https://labtestsonline.org/understanding/analytes/blood-typing/tab/faq
Lab Tests Online [Internet]. American Association for Clinical Chemistry; c2001–2017. Glossary: Antigen [cited 2017 Sep 29]; [about 3 screens]. Available from: https://labtestsonline.org/glossary/antigen
Lab Tests Online [Internet]. Washington D.C.: American Association for Clinical Chemistry; c2001–2017. RBC Antibody Screen: The Test [updated 2016 Apr 10; cited 2017 Sep 29]; [about 4 screens]. Available from: https://labtestsonline.org/understanding/analytes/antiglobulin-indirect/tab/test
Lab Tests Online [Internet]. Washington D.C.: American Association for Clinical Chemistry; c2001–2017. RBC Antibody Screen: The Test Sample [updated 2016 Apr 10; cited 2017 Sep 29]; [about 3 screens]. Available from: https://labtestsonline.org/understanding/analytes/antiglobulin-indirect/tab/sample
Mayo Clinic [Internet]. Mayo Foundation for Medical Education and Research; c1998–2017. Tests and Procedures: Rh factor blood test; 2015 June 23 [cited 2017 Sep 29]; [about 3 screens]. Available from: http://www.mayoclinic.org/tests-procedures/rh-factor/basics/definition/PRC-20013476?p=1
National Heart, Lung, and Blood Institute [Internet]. Bethesda (MD): U.S. Department of Health and Human Services; What Are the Risks of Blood Tests? [updated 2012 Jan 6; cited 2017 Sep 29]; [about 5 screens]. Available from: https://www.nhlbi.nih.gov/health/health-topics/topics/bdt/risks
National Heart, Lung, and Blood Institute [Internet]. Bethesda (MD): U.S. Department of Health and Human Services; What is Rh Incompatibility? [updated 2011 Jan 1; cited 2017 Sep 29]; [about 2 screens]. Available from: https://www.nhlbi.nih.gov/health/health-topics/topics/rh
National Heart, Lung, and Blood Institute [Internet]. Bethesda (MD): U.S. Department of Health and Human Services; What To Expect with Blood Tests [updated 2012 Jan 6; cited 2017 Sep 29]; [about 4 screens]. Available from: https://www.nhlbi.nih.gov/health/health-topics/topics/bdt/with
NorthShore University Health System [Internet]. NorthShore University Health System; c2017. Community & Events: Blood Types [cited 2017 Sep 29]; [about 3 screens]. Available from: https://www.northshore.org/community-events/donating-blood/blood-types
Quest Diagnostics [Internet]. Quest Diagnostics; c2000–2017. Clinical Education Center: ABO Group and Rh Type [cited 2017 Sep 29]; [about 3 screens]. Available from: https://education.questdiagnostics.com/faq/FAQ111
University of Rochester Medical Center [Internet]. Rochester (NY): University of Rochester Medical Center; c2017. Health Encyclopedia: Red Blood Cell Antibody [cited 2017 Sep 29]; [about 2 screens]. Available from: https://www.urmc.rochester.edu/encyclopedia/content.aspx?contenttypeid=167&contentid=red_blood_cell_antibody
UW Health [Internet]. Madison (WI): University of Wisconsin Hospitals and Clinics Authority; c2017. Health Information: Blood Type Test [updated 2016 Oct 14; cited 2017 Sep 29]; [about 3 screens]. Available from: https://www.uwhealth.org/health/topic/medicaltest/blood-type/hw3681.html

The medical information provided is for informational purposes only, and is not to be used as a substitute for professional medical advice, diagnosis or treatment. Please contact your health care provider with questions you may have regarding medical conditions or the interpretation of test results.

In the event of a medical emergency, call 911 immediately.