NIPT provides fewer false-positive and false-negative results than combined first trimester screening for trisomy 21, 18 and 13.
It is important to note that NIPT is a screening test and does not provide a definitive genetic diagnosis, as NIPT cannot differentiate potential chromosome differences between the placenta and fetus. A definitive genetic diagnosis of the fetus requires cytogenetic analysis of either amniotic fluid or chorionic villus sampling (CVS).
Combined first trimester screening82%1 in 26 NIPT>99%<1 in 1,000 Accuracy (T21, T18, T13)Sensitivity*False-positive rate#
* Proportion fetuses with trisomy correctly identified by the test as high probability of disorder.
# Proportion of normal fetuses incorrectly identified by the test as high probability of disorder.
NIPT Performance data in a general screening population
Trisomy 21>99.9% (95% CI:97.1%)>99.90% (95% CI:99.63%) Trisomy 18>99.9% (95% CI:91.4%)>99.90% (99.64% CI:97.1%) Trisomy 13>99.9% (95% CI:87.1%)>99.90% (95% CI:99.64%)