<prompt> All of the following antenatal screening tools indicate increased risk of Down syndrome EXCEPT?Decreased Nuchal fold thicknessIncreased Inhibin levelAbsence of nasal boneDecreased PAPP-A level  <response>: Antenatal Screening for Downs Syndrome USG - Nuchal Thickness 3 mm 11 - 14 weeks of gestation - Absence of nasal bones - Sho femur - Duodenal Atresia Biochemical Tests 1st Trimester - b-HCG, PAPP-A Pregnancy associated Plasma Protein - A Dual Test 2nd Trimester QTriple Test - AFP a-Fetoprotein b-hCG Unconjugated Estirol Quadruple Test - Triple Test Inhibin Mnemonic HI High : HCG Inhibin levels increase in Down syndrome Integrated Test - Best test screening Downs syndrome Sensitivity - 95-97 - Maternal age 1st Trimester NT PAPP-A Quadruple Test 2nd Trimester Confirmatory test for antenatal Dx of Down syndrome - Fetal karyotyping, for which genetic material may be obtained by- - Chorionic Villous Sampling CVS - Amniocentesis - Cordocentesis Percutaneous Umbilical cord Blood sampling But these are invasive procedures that carry risk of aboion. 