I went for the D/S test which has Nuchal Translucency information using ultrasound and then a blood test measuring βhCG is a hormone and PAPP-A a protein which are produced by the placenta. The levels of these substances give a part assessment of your risk of Down's syndrome and the result forward to the ultrasound provider and both the ultrasound result and blood test result are computed to check for the result by a genetic counsellor.