The quad screen — also known as the Quadrupal Marker test, the second-trimester screen or merely the quad test — is a prenatal test that measures levels of four substances in pregnant women’s blood:
- Alpha-fetoprotein (AFP), a protein made by the developing baby
- Human chorionic gonadotropin (HCG), a hormone produced by the placenta
- Estriol, a hormone produced by the placenta and the baby’s liver
- Inhibin A, another hormone made by the placenta
Reasons to take Quadrupal Marker Screening:
The quad screen evaluates your chance of carrying a baby who has any of the following conditions:
- Down syndrome (trisomy 21)
- Trisomy 18
- Spina bifida
- Abdominal wall defects
The quad screen has traditionally been one of the most commonly used screenings in the second trimester. It was generally used if prenatal care began during the second trimester or if first-trimester screening, which involves a blood test and an ultrasound exam, wasn’t available.
Risks of taking Quadrupal Marker Screening:
The quad screen is a routine prenatal screening test. The test poses no risk of miscarriage or other pregnancy complications.As with other prenatal screening tests, however, the quad screen can cause anxiety about the possible test results and what they might mean for your baby.