Final answer:
The quad+ screen is a prenatal blood test that measures levels of AFP, uE3, hCG, and Inhibin A to assess risk for birth defects or genetic disorders.
Step-by-step explanation:
The quad screen is a prenatal test that measures levels of four substances in a pregnant woman's blood:
- Alpha-fetoprotein (AFP), which is produced by the fetus and placenta.
- Unconjugated estriol (uE3), an estrogen produced by the fetus and the placenta.
- Human chorionic gonadotropin (hCG), a hormone produced by the placenta.
- Inhibin A, a hormone produced by the ovaries and the placenta.
Collectively, these measurements can help assess risk for certain birth defects or genetic disorders, including Down syndrome (trisomy 21), Edward's syndrome (trisomy 18), and neural tube defects such as spina bifida.