[The noninvasive prenatal testing for Down's Syndrome. Retrospective study of 8821 patients]

Objective: To demonstrate the decrease in intrauterine invasive procedures through analysis of DNA fetoplacental free circulating in maternal blood: Non Invasive Prenatal Test (NIPT), in Prenatal Diagnosis Center of American Hospital of Paris (AHP).

Materials and methods: Retrospective descriptive study of 8821 patients in Prenatal Diagnosis Center at the AHP between 01/01/2012 and 09/25/2014. The NIPT is available to patients since 1st January 2013.

Results: The number of invasive procedures decreased significantly (P<0.0001) between 2012 (n=1177, i.e. 42 % of the global activity of the Prenatal Diagnosis Center at the AHP in 2012) and 2013 (n=987 or 28.5 %) and between 2013 and 2014 (n=599 or 23.4 %). The NIPT calculated performance statistics are: sensitivity≥99.9 %; specificity=99.8 %; Positive Predictive Value=90.4 %; Negative Predictive Value≥99.9 %; False Positives=3. While the actual screening statistic values are: sensitivity≥95.4 %; specificity=82.5 %; Positive Predictive Value=6.5 %; Negative Predictive Value=99.9 %; False Positives=1197. The NIPT has reduced the number of invasive procedures at the Prenatal Diagnosis Center at the AHP. The NIPT performances are superior to those of the actual screening.