Triple Screen & Quad Screen Tests

Tests that go beyond alpha-fetoprotein testing are available now to help your doctor determine if your child might have Down syndrome and to rule out other problems in your pregnancy.

The Triple Screen Test

The triple-screen test helps identify problems using three blood components: alpha-fetoprotein, human chorionic gonadotropin (HCG) and a form of estrogen produced by the placenta called unconjugated estriol.

Abnormal levels of these three blood chemicals can indicate Down syndrome. For older mothers, the detection rate is higher than 60%, with a false-positive rate of nearly 25%. Abnormal results of a triple-screen test are usually double-checked with ultrasound and amniocentesis.

The Quad Screen Test

The quad-screen test is similar to the triple-screen but adds a fourth measurement-the blood level of inhibin-A, a chemical produced by the ovaries and the placenta. This fourth measurement raises the sensitivity of the standard triple-screen test by 20% in determining if a fetus has Down syndrome. The quad-screen test identifies almost 80% of fetuses with Down syndrome. It has a false-positive rate of 5%.