A new blood test for pregnant women, taken around the end of the first trimester of pregnancy, has proven much more effective than existing standard noninvasive screening tests at identifying trisomy 21 which accounts for 90% of Down’s Syndrome cases, according to a study published in the New England Journal of Medicine (one of the most prestigious medical journals in existence).
The 15,803 women were tested using the old standard screening and the new test.
There were 38 pregnancies in the sample with this genetic defect.
The old standard screening missed 8 of 38 pregnancies with this genetic defect and had 854 false positives. Only 3.4% of positives on the old standard screening test were correct, and 21.1% of true positives were missed.
The new screening test missed no pregnancies with genetic defects and had 9 false positives (a more than 98% improvement in the false positive rate). Of those 9 false positives, 8 out of 9 were also false positives on the old standard screening test. 80.9% of positives on the new screening test were correct.
Among 11,994 women at low risk, there were 19 true positives and 6 false positives with the new screening test. For low risk women, 76.0% of positives on the new screening test were correct.
Among 3,809 women at high risk, there were 19 true positives and 3 false positives with the new screening test. For high risk women, 86.4% of the positives on the new screening test were correct.
Something on the order of 50% to 90% of pregnancies that are confirmed to have trisomy 21 are terminated.
from Wash Park Prophet http://ift.tt/1ESMu7U
via Denver News