This is the screening test for Down’s syndrome at 16-21 weeks of gestations. It only involves blood taking from pregnant lady. The “Dual test” measures the maternal serum level of alpha fetal protein and human Chorionic Gonadotropin with addition of maternal age to calculate the risks of Down’s syndrome. The detection rate of Dual test is only around 60%. The “Triple test” measures an additional marker of the Dual test, called estriol. The detection rate of Triple test is around 70%