Prenatal Panel

A prenatal panel, also known as a prenatal screening test or multiple marker screen, is a series of blood tests performed during pregnancy to assess the risk of certain genetic disorders and birth defects.

What does the test measure?

The prenatal panel typically measures the levels of several substances in the mother's blood, including:

• Alpha-fetoprotein (AFP): a protein produced by the fetus
• Estriol (E3): an estrogen produced by the placenta and fetus
• Human chorionic gonadotropin (hCG): a hormone produced by the placenta
• Inhibin A: a protein produced by the placenta

What is the purpose of the test?

The prenatal panel is used to:

• Detect potential genetic disorders, such as Down syndrome (trisomy 21), trisomy 18, and trisomy 13
• Identify increased risk for neural tube defects, such as spina bifida
• Assess the risk of other birth defects, such as abdominal wall defects

When is the test performed?

The prenatal panel is typically performed between 15 and 20 weeks of gestation, during the second trimester of pregnancy.

How is the test interpreted?

The results of the prenatal panel are interpreted based on the levels of the substances measured in the mother's blood. The results are then used to calculate the risk of certain genetic disorders and birth defects.

• A low risk result indicates that the likelihood of a genetic disorder or birth defect is low
• A high risk result indicates that the likelihood of a genetic disorder or birth defect is increased, but it does not provide a definitive diagnosis

What are the next steps after an abnormal result?

If the prenatal panel results indicate an increased risk for a genetic disorder or birth defect, additional testing may be recommended, such as:

• Aminocentesis: a procedure in which a sample of amniotic fluid is taken from the uterus to test for genetic disorders
• Chorionic villus sampling (CVS): a procedure in which a sample of placental tissue is taken to test for genetic disorders
• Ultrasound: a non-invasive imaging test used to evaluate fetal development and detect potential birth defects

Limitations of the test

The prenatal panel is not a diagnostic test, but rather a screening test. It can provide false positive or false negative results.

• A false positive result may indicate an increased risk for a genetic disorder or birth defect when none exists
• A false negative result may fail to detect a genetic disorder or birth defect that is present