Quadraple Marker
The quadruple marker test, also known as the quad screen or quadruple screen test, is a prenatal screening test used to evaluate the risk of certain chromosomal abnormalities and neural tube defects in the fetus. It is an extension of the triple marker test and typically measures the levels of four substances in the mother’s blood:
- Alpha-fetoprotein (AFP): AFP is a protein produced by the fetus and is normally found in the mother's blood during pregnancy. Abnormal levels of AFP may indicate an increased risk of neural tube defects such as spina bifida or anencephaly.
- Human chorionic gonadotropin (hCG): hCG is a hormone produced by the placenta during pregnancy. Abnormal levels of hCG may be associated with an increased risk of chromosomal abnormalities such as Down syndrome (trisomy 21) or Edwards syndrome (trisomy 18).
- Estriol: Estriol is a hormone produced by both the fetus and the placenta during pregnancy. Abnormal levels of estriol may also be associated with an increased risk of chromosomal abnormalities.
- Inhibin A: Inhibin A is a hormone produced by the placenta during pregnancy. Abnormal levels of inhibin A may also be associated with an increased risk of chromosomal abnormalities.