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 & 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” & 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 & 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 & 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 & 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 & 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 will 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 will am 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 will am need to know about an RBC antibody screen?
Rh incompatibility is not common. Most people are Rh positive, which does not cause blood incompatibility & poses no health risks.