The Double Marker test is one of the many pregnancy tests a pregnant woman has to undergo. It is usually done between 9 to 13 weeks of pregnancy. Mostly, it will be combined with an Ultrasound test. Since pregnancy tests are scheduled according to the growth of the fetus, going for the test during the 12 weeks of pregnancy can help in identifying if the unborn child is likely to develop any sort of chromosomal imbalance or mental disorders.

This test is done with blood sample and it checks for two markers namely, Free Beta hCG (human chorionic gonadotrophin and PAPP-A (pregnancy-associated plasma protein A). High level of hCG and Low level of PAPP-A is a clear sign of risk of mental disorders.

Generally,pregnant women above 35 years of age carry a high risk of delivering a child with Down's syndrome. However, it is recommended even for younger age women.