Pregnancy: Quad Marker Screen


What is a quad screen?

During your pregnancy, you will see your healthcare provider every few weeks. Some visits include blood tests and other screenings to keep a close eye on your baby’s health. The quad screen, or quad marker screen, is one test you may have during your second trimester. “Quad” refers to the fact that the screening tests four factors in your blood.

The quad screen is a simple blood test that your provider may do between the 15th and 20th weeks of pregnancy. It can help your healthcare provider determine if your fetus has the marker or sign for Down syndrome and other genetic disorders.

When do I need to have the quad screen done?

Your healthcare provider will ask you if you want the quad marker screen during your second trimester. If you decide to have the screening, it will be between the 15th and 20th weeks of your pregnancy, counting from the first day of your last menstrual period. You’ll get the most accurate results between the 16th and 18th weeks.

Your healthcare provider may recommend having a quad screen if you:

  • Are 35 years or older.
  • Had a viral infection during your pregnancy.
  • Have a family history of congenital disabilities (birth defects).
  • Have been exposed to high levels of radiation.
  • Have diabetes and use insulin.
  • Used harmful medications or drugs while pregnant.

Test Details

How is the quad marker screen done, and is it safe?

The quad screen involves drawing a little blood. A lab technician gets enough of a blood sample from one of your veins to run the screen. It is safe for your baby and only requires a needle poke for the mother.

What does the quad screen check?

A quad screen checks for four things in your blood:

  • Alpha-fetoprotein (AFP): Your baby’s liver produces AFP. Levels higher than expected could mean the baby has a neural tube defect, such as spina bifida or anencephaly. But it can also mean that the pregnancy is farther along than you thought. Or you may be carrying twins. Low AFP levels could mean a higher risk of having a baby with Down syndrome.
  • Unconjugated estriol (UE): Your baby and placenta (the structure providing nutrients to your baby) produce this hormone. Low levels indicate a higher risk of having a baby with Down syndrome.
  • Human chorionic gonadotropin (hCG): The placenta makes a hormone called hCG, which the screening detects. Levels that are higher than expected could mean an increased risk of having a baby with Down syndrome.
  • Inhibin-A: Your placenta and ovaries produce this protein. The risk of having a baby with Down syndrome increases with higher-than-expected levels of this protein.

As your pregnancy goes on, the levels of these substances change. These changes alert the healthcare provider to possible genetic disorders.

It’s important to understand that the quad marker screening doesn’t mean the baby has a genetic disorder. It means the risk is higher.

Results and Follow-Up

What does a normal quad screen result mean?

A normal quad marker test result means you don’t have a higher risk for having a baby with birth defects. Your provider most likely won’t suggest additional genetic tests. No tests can guarantee a completely healthy baby or uncomplicated pregnancy.

What does an abnormal result mean?

The quad screen only checks your risk. It doesn’t tell you if your baby will have a genetic disorder. So, an abnormal result means you may need further testing. It can also mean your baby is older than you and your healthcare provider thought.

If your quad screen shows an increased risk, your healthcare provider will suggest other tests. These tests help determine if your baby has a genetic disorder. Your healthcare provider may recommend an ultrasound or amniocentesis.

Additional Details

Do I need to have a quad marker screen?

While many healthcare providers recommend the quad marker, you make the final decision. You can choose to have a screen or not. Healthcare providers strongly recommend you have it if you meet these criteria:

  • Age: Women 35 and over when the baby is due.
  • Diabetes: Women with insulin-dependent diabetes.
  • Family history: Women with a family history of congenital disabilities.
  • Previous congenital disability: Women who have had a child with a congenital disability.

A note from Cleveland Clinic

Having a baby can be an exciting time filled with a wide range of emotions. Healthcare providers understand how your pregnancy makes you feel. With good prenatal care, your provider can monitor your pregnancy to keep you and your baby safe. If you are worried about your baby’s health, talk to your healthcare provider about your concerns.

Last reviewed by a Cleveland Clinic medical professional on 11/05/2020.


  • American College of Obstetricians and Gynecologists. Prenatal Genetic Screening Tests. ( Accessed 11/6/2020.
  • American Pregnancy Association. Quad Screen Test. ( Accessed 11/6/2020.
  • Centers for Disease Control and Prevention. Diagnosis of Birth Defects. ( Accessed 11/6/2020.
  • Dugoff, Lorraine, et al. Quad Screen as a Predictor of Adverse Pregnancy Outcome. ( Obstetrics & Gynecology. 2005 Aug; 106(2): 260-267. Accessed 11/6/2020.
  • March of Dimes. Prenatal Tests. ( Accessed 11/6/2020.
  • Prenatal Information Research Consortium. ACOG/SMFM Issue New Guidelines for Prenatal Genetic Screening. ( Accessed 11/6/2020.

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