Dr Mobeen Taj kgn hospital on Instagram: "#Double marker test is a prenatal screening test done during pregnancy to assess the risk of chromosomal abnormalities, such as Down syndrome. It measures two substances in the blood: - Beta-hCG (human chorionic gonadotropin) - PAPP-A (pregnancy-associated plasma protein-A) The test is usually done between 11-13 weeks of pregnancy, along with an ultrasound (NT scan). Results help identify high-risk pregnancies, and further testing (e.g., amniocentesis) m