Your Pregnancy > About the Maternal Serum Alpha Test

About the Maternal Serum Alpha Test

The alpha-fetoprotein test is a screening test used to check for certain abnormalities that may be present in the developing baby.

The developing baby produces a protein called alpha-fetoprotein. Some of this protein gets into the fluid around the baby and some into the mother's blood. This test involves taking blood from the pregnant patient and measuring the level of protein in it.

Very high levels may indicate a need for further testing, as may very low levels. This is a screening test - it does not diagnose anything, but it shows who may require further testing.

Various abnormalities in the baby may cause the level to be too high or too low. Usually, the problem is an incorrect due date, twins, or something else. Sometimes, an abnormal level is due to an abnormality in the baby. Very high levels may indicate a baby with a defect, causing the brain or spinal cord to be exposed. Also, some babies with mongolism (Down Syndrome) have very low levels.

In the event of abnormal test results, we recommend follow up with an ultrasound exam. If this doesn't explain the abnormality, we may suggest amniocenteses. This involves removing fluid from around the baby to further test for possible abnormalities.

There are two things you must understand about the test. A normal test is reassuring, but does not guarantee the baby is normal. Some abnormal babies have normal alpha-fetoprotein levels. Also, abnormal test usually does not mean the baby is abnormal. It usually means we need to check the baby with ultrasound to see if the due date is accurate or if you are carrying twins.

There will be separate charge by the laboratory doing this test. Your insurance may not cover these charges.

The test is done between 16 and 18 weeks of pregnancy. Not everyone wants to be tested.