<s>[INST] Hello doctor,My wife is 28 years old and is in her 13th week of pregnancy. We had an NT test a couple of days back. The NT was 1.7mm. Trisomy 21 had an adjusted scale of 1:3428. Our doctor has advised us to go for a double marker test. The results will be out in two to three days. Is a risk of 1 in 3428 considered medium to high, to go for a blood test? Is there any relation between double marker test and NT? Is it possible that double marker test results may increase the risk from 1 in 3400s to less than 1 in 300? How are the results of NT and double marker combined? I know it is premature for these thoughts, but the anxiety in waiting for the double marker is killing my wife (and me). I thought of having a first cut understanding of how it works. [/INST] Hello. I hope that the above answer satisfies you and your wife. Have patience and faith in the God, so that, positive thoughts supervene. Good luck. For more information consult an obstetrician and gynaecologist online --> </s>