What to do after positive double marker test for Trisomy 21 & normal NT scan? – Dr. Nupur Sood

As a routine to screen for any chromosomal abnormality especially 16, 18 and 21 we do the double marker or quadruple marker. But these are not the specific tests. They will only tell you whether you are in the low risk category or high risk category. If you are in the high risk category you should go for some further investigations. It just say that you are on the higher risk of having a Down’s syndrome baby. Then you need to confirm it further. If your Neuchal Translucency Scan NT Scan is coming normal then the chances are good that it is all going normal. If it has still some high risk factors like IVF conceived baby, age group more than 35, there are certain other medical disorders like diabetes or some hereditary disorder in the family, previous Downs baby, in these cases we go in for further testing called as amniocentesis where the fluid around the baby has certain cells of the baby which can be picked up by ultrasound guidance and they are the test for confirming the diagnosis whether it is a normal or abnormal baby. Since it is an invasive test it is usually given second preference and something non-invasive and simple blood test like a double marker, quadruple marker is what is suggested initially. There is also a certain blood test which can be done instead of this invasive amniocentesis. But this is still under research work and at present we are continuing with amniocentesis if you want to confirm the diagnosis.