Quadruple Marker Second Trimester is conducted between 14 to 22 weeks of gestation, this screening test measures four markers i.e., Alpha-fetoprotein (AFP), Human Chorionic Gonadotropin (hCG), Estriol, and Inhibin-A. The Quadruple Marker test offers a more comprehensive assessment of the risk for chromosomal abnormalities, including Down syndrome (Trisomy 21) and Edwards syndrome (Trisomy 18), as well as neural tube defects. It helps in making informed decisions regarding further diagnostic testing.