In this Article

• Introduction
• What happens during the test?
• When should I get a quad marker screen?
• What substances are measured during a quad marker screen?
• Is the quad marker screen safe?
• What does it mean if the quad marker screen results are normal?
• What does it mean if the quad marker screen results are abnormal?
• Should I have the quad marker screen?
• Quad Marker Screen Test Index

What Substances Are Measured During a Quad Marker Screen?

The blood sample is sent to a laboratory and tested for the presence of the following four substances, which are normally found in the baby's blood, brain, spinal fluid and amniotic fluid:

• Alpha-fetoprotein (AFP). A protein produced by the baby's liver.
• Unconjugated Estriol (UE). A protein produced in the placenta and in the baby's liver.
• Human Chorionic Gonadotrophin (hCG). A hormone produced by the placenta.
• Inhibin-A. A hormone produced by the placenta.

The expected amount of these substances normally found in the mother's bloodstream changes each week of pregnancy, so it is important to tell your health care providers how far along you are in your pregnancy. High AFP levels may indicate that the baby has an open neural tube defect. High AFP levels may also indicate that the fetus is older than was thought or that the woman is expecting twins. Lower than normal AFP levels could indicate that a woman is at higher risk for having a baby with Down syndrome.

Levels of hCG and Inhibin-A are higher than normal when a woman has an increased risk of having a baby with Down syndrome. Lower than normal levels of Estriol may also indicate that a woman is at high risk for having a baby with Down syndrome.

Is the Quad Marker Screen Safe?

Yes. The quad marker screen is a safe and useful screening test for families concerned about birth defects or genetic diseases. It is a test that carries no risk to the baby, since a blood sample is taken only from the mother.

What Does It Mean if the Quad Marker Screen Results Are Normal?

Normal levels of AFP, estriol, hCG and Inhibin-A strongly indicate that you have a healthy pregnancy and a healthy baby. In over 98% of pregnancies, normal quad marker screen results predict healthy babies and births without major complications. However, there are no prenatal tests that can guarantee your baby and pregnancy will be completely healthy or without complications.

Suggested Reading by Our Doctors

• Amniocentesis - Learn about amniocentesis, a procedure that examines the chromosomes of the fetus to determine lung maturity, and the possiblities of birth defects.
• Pregnancy (Stages - Trimesters of Pregnancy) - Learn what to expect during the three phases of pregnancy (1st, 2nd, 3rd trimester). Find out what changes in your body to expect, and how your baby will develop week by week.
• Alpha-fetoprotein Blood Test -

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