Summary

The red cell antibody screen looks for circulating antibodies in your blood that target and destroy red blood cells other than your own. These become important to screen for if you are having a blood transfusion from a donor, or if you are pregnant. The antibodies react if you are transfused with blood that is different to yours. Screening can ensure that the donor blood is fully compatible with your own and it is safe for you to have. In pregnancy a baby can inherit red blood cells from its father that are not compatible with the mother and she may develop antibodies that can harm the developing baby.

Why get tested?

The surface of every red blood cell is coated with proteins or sugars called antigens. Everyone has their own set of antigens which are inherited from their parents. The most common antigens or surface identifiers are the O, A, and B antigens, and a person’s blood is grouped into an A, B, AB, or O blood type according to the presence or absence of these antigens.

Another important surface antigen is Rh factor, also called D antigen. If it is present on a person’s red blood cells, that person’s blood type is Rh+ (positive). If it is absent, the blood is type Rh- (negative). For more information on how blood groups are identified, and blood group antigens see the Test called Blood Groups.

If you are exposed to someone else's blood, which has different antigens to your own, your immune system can generate antibodies to them, just as it does to bacteria or viruses.

The problem is more common in people receiving multiple transfusions because they are being repeatedly exposed to different red blood cell antigens in each successive transfusion. For these patients, laboratories will test the blood group, red cell antibody screening and cross match tests every 72 hours on a new blood sample. This ensures that each transfusion uses blood that doesn't contain antigens that will react with any antibodies that are detected immediately before transfusion.

In pregnancy, the concern is that red cell antibodies can form in the mother's blood if the baby has different antigens to the mother.  They can destroy the blood cells of the baby giving rise to the condition known as haemolytic disease of the foetus and newborn (HDFN). This may not happen with the first pregnancy and is more likely with the second or succeeding pregnancies. If an antibody is found in routine prenatal testing, your doctor may want to monitor your pregnancy more thoroughly to minimise the risk of HDFN.

Having the test

Sample

Blood

Any preparation?

None

Your results

If you are one of those people who have antibodies to red blood cell antigens other than A, B or Rh, the results will be used to select blood that is without the corresponding antigens and therefore safe for you to have.

Questions to ask your doctor

The choice of tests your doctor makes will be based on your medical history and symptoms.   It is important that you tell themeverything you think might help. 

You play a central role in making sure your test results are accurate. Do everything you can to make sure the information you provide is correct and follow instructions closely. 

Talk to your doctor about any medications you are taking. Find out if you need to fast or stop any particular foods or supplements. These may affect your results. Ask:

• Why does this test need to be done?
• Do I need to prepare (such as fast or avoid medications) for the sample collection?
• Will an abnormal result mean I need further tests?
• How could it change the course of my care?
• What will happen next, after the test?

More information

Pathology and diagnostic imaging reports can be added to your My Health Record. You and your healthcare provider can now access your results whenever and wherever needed.    
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