Red Blood Cell Antibody Screen Test
This test checks for red blood cell (RBC) antibodies in your blood. These antibodies can form after a blood transfusion or during pregnancy if you are exposed to blood that is different from your own. The test helps prevent serious reactions during transfusions and protects the fetus during pregnancy.
What this test measures
An RBC antibody screen looks for antibodies that your immune system makes against foreign red blood cells. These antibodies can destroy red blood cells that have different antigens (markers) than your own.
What your results mean
Reference ranges vary by laboratory and by your age and sex. MedlinePlus does not publish a single normal range for this test — always read your result against the range printed on your own lab report and discuss it with your provider.
Higher-than-normal results
A positive result means you have one or more RBC antibodies in your blood. For transfusions, this means you need special donor blood. For pregnancy, it means the antibodies could harm the fetus, and you will need more tests and monitoring.
Lower-than-normal results
A negative result means no RBC antibodies were found. For pregnancy, if you are Rh-negative, your provider may give you an injection to prevent your body from making Rh antibodies.
Frequently asked questions
Why is this test done before a blood transfusion?
The test helps your health care provider select donor blood that is well matched with your blood to prevent a serious immune reaction.
What does a positive result mean during pregnancy?
It means you have RBC antibodies that could harm your fetus. You will likely need more tests to find out what type of antibodies you have.
Can RBC antibodies be treated?
There is no treatment to stop your body from making more Rh antibodies. If you have other RBC antibodies, your pregnancy will be closely watched.
What is Rh incompatibility?
Rh incompatibility occurs when you are Rh-negative and your fetus is Rh-positive. Your immune system may make Rh antibodies that can attack the fetus's red blood cells.
Will I always have RBC antibodies once they form?
Yes, once your body makes RBC antibodies, you will always have them.
Related lab tests
Sources
- MedlinePlus: Red Blood Cell Antibody Screen — NIH MedlinePlus
Last updated . Information is aggregated from official public sources and is not a substitute for professional medical care.