Q: I am a 35 years old pregnant woman and have got a triple test done in the 14th week of my pregnancy and the results obtained are: AFP - 24.8 ng/ml, FE3 - 0.6 ng/ml, HCG - 97689.2 mIU/ml, trisomy 21 was screen positive (>1:50). My gynaecologist has advised me to get a repeat of triple test done. Please advise if amniocentesis or foetal abnormality scan should be performed. Which one is better?

A:The triple test is a good screening test only. The ultrasound can pick up anomalies only if done by a trained sonologist with experience in level 11 scanning and can be correctly diagnosed in about 80% cases in trained hands. The amniocentesis is usually reserved when the diagnosis is unclear on scanning, which can happen, and is the most accurate, from a reputed lab. It is not a selection of one test over the other, but a stepwise procedure to be able to arrive at the diagnosis. Occasionally, all three maybe required.