Quadruple test

The Quadruple test – also known as the Quad screen or simply the Quad test – is a prenatal screening test that measures levels of four hormones in a your blood:

  • Alpha-fetoprotein (AFP), a protein made by the developing baby
  • Beta Human chorionic gonadotropin (B HCG), a hormone made by the placenta
  • Estriol, a hormone made by the placenta and the baby’s liver
  • Inhibin A, another hormone made by the placenta

The quad screen is typically done between weeks 15 and 20w6d of pregnancy — the second trimester.

Quad screen is a screening test  which indicates your risk of carrying a baby who has certain chromosomal conditions, like Down syndrome. The alpha-fetoprotein part of the test can also help in detecting neural tube defects, like spina bifida and anencephaly.
If the test results show low risk, the quad screen can offer reassurance of a healthy pregnancy.

If the test results show intermediate or high risk, more definitive tests might be offered.

Why it’s done?

The quad screen is done to evaluate your risk of carrying a baby who has any of the following conditions:

  • Down syndrome (trisomy 21). Down syndrome is a genetic condition where there is and extra 21st chromosome, which may cause lifelong impairments in mental and social development, as well as various other physical concerns.
  •  Edwards syndrome (trisomy 18). Edwards syndrome is a genetic condition that causes severe developmental delays and is usually associated with structural defects in the fetus. Edwards syndrome is often fatal by age 1.
  • Spina bifida. Spina bifida is a serious defect in the fetus in which the tissue surrounding a baby’s developing spinal cord has not closed properly. Babies with spina bifida might need corrective surgeries in the future. Spine bifida can lead to severe physical and mental disabilities.
  •  Anencephaly. Anencephaly is a lethal condition where the brain is underdeveloped with an incomplete skull. A baby born with anencephaly might be stillborn or survive only a few hours to days after birth.

Depending on the timing, your doctor might recommend other prenatal screening tests — such as first trimester screening, which involves a blood test and an ultrasound exam — in addition to the quad screen or in place of the quad screen.

Remember, the quad screen is an optional test. It is only a screening test and the test results only indicate whether you have an increased risk of carrying a baby with Down syndrome, not whether your baby actually has the condition.

Before the screening, think about what the results mean to you. Consider whether the screening will be worth any anxiety it might cause, or whether you’ll handle your pregnancy differently depending on the results.
You might also consider what level of risk would be enough for you to choose a more invasive follow-up test.


The quad screen is a routine prenatal screening test using mother’s blood. There are no risks associated with the test either to the mother or the fetus.