Quadruple Screen (Quad Screen)

Who Gets the Test?

The quad screen is a test done in the second trimester to check for some birth defects. Women who are 35 or older, or who have a family history of genetic disease, are more likely to get the quadruple screen. However, any woman can ask for this test.

The quadruple screen has replaced an earlier test -- the triple screen -- in the U.S.

Doctors sometimes combine the results of the quad test with a separate test, the first trimester screening. This is called integrated or sequential screening. It's more accurate than either test by itself.

What the Test Does

The quad screen can help estimate your baby's risk of Down syndrome, Edward's syndrome (trisomy 18), and neural tube defects. It works by testing the levels of four substances in your blood: alpha-fetoprotein (AFP), human chorionic gonadotropin, estriol, and inhibin A.

The quad screen can't tell you for sure if your baby will have one of these problems. It only shows if your baby has a higher risk. Most women who have unusual results on the test go on to have a perfectly healthy baby.

Whether you get this test is your choice. Some women want to know the results so they can prepare. Others don't. They may decide that knowing the results wouldn't change anything. Or they feel that the test could result in unnecessary stress and invasive follow-up testing. Some doctors feel it's helpful to know the results of this test so they can better monitor your pregnancy and delivery.

How the Test Is Done

The quad screen is a simple blood test. There's no risk to you or your baby. A technician will take a small sample from your arm. It takes five to 10 minutes.

What to Know About Test Results

You should have the results in a few days. If your quad screen is negative, your baby has a low risk of these birth defects. If it's positive, try not to worry. Your doctor may recommend further tests to rule out problems. These could include ultrasounds or amniocentesis.

How Often the Test Is Done During Your Pregnancy

You would get the quad screen once between 15 and 20 weeks. It may be most accurate between 16 to 18 weeks.

Other Names for This Test

Multiple-marker screening test, integrated screening (when combined with the first trimester screening)

Tests Similar to This One

Triple screen, MSAFP

WebMD Medical Reference Reviewed by Traci C. Johnson, MD on October 5, 2016

Sources

SOURCES:

ACOG: "Screening for Birth Defects."

Johns Hopkins Manual of Gynecology and Obstetrics, 4th Edition. Lippincott Williams & Williams, 2010.

MyMidwife.org: "Second Trimester Tests."

© 2016 WebMD, LLC. All rights reserved.

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