Comparison of first‐tier cell‐free DNA screening for common aneuploidies with conventional publically funded screening. (21st November 2017)

• Record Type: Journal Article
• Authors: Langlois, Sylvie; Johnson, JoAnn; Audibert, François; Gekas, Jean; Forest, Jean‐Claude; Caron, André; Harrington, Keli; Pastuck, Melanie; Meddour, Hasna; Tétu, Amélie; Little, Julian; Rousseau, François
• Is Part Of: Prenatal diagnosis. Volume 37:Number 12(2017)
• Page Start: 1238
• Page End: 1244
• Publication Date: 2017-11-21
• Subjects: Prenatal diagnosis -- Periodicals; Fetus -- Diseases -- Diagnosis -- Periodicals; Electronic journals; 618.32075
• DOI: 10.1002/pd.5174
• Languages: English
• ISSNs: 0197-3851

Abstract

Abstract: Objective: This study evaluates the impact of offering cell‐free DNA (cfDNA) screening as a first‐tier test for trisomies 21 and 18. Methods: This is a prospective study of pregnant women undergoing conventional prenatal screening who were offered cfDNA screening in the first trimester with clinical outcomes obtained on all pregnancies. Results: A total of 1198 pregnant women were recruited. The detection rate of trisomy 21 with standard screening was 83% with a false positive rate (FPR) of 5.5% compared with 100% detection and 0% FPR for cfDNA screening. The FPR of cfDNA screening for trisomies 18 and 13 was 0.09% for each. Two percent of women underwent an invasive diagnostic procedure based on screening or ultrasound findings; without the cfDNA screening, it could have been as high as 6.8%. Amongst the 640 women with negative cfDNA results and a nuchal translucency (NT) ultrasound, only 3 had an NT greater or equal to 3.5 mm: one had a normal outcome and two lost their pregnancy before 20 weeks. Conclusions: cfDNA screening has the potential to be a highly effective first‐tier screening approach leading to a significant reduction of invasive diagnostic procedures. For women with a negative cfDNA screening result, NT measurement has limited clinical utility. Abstract : What is already known about this topic? cfDNA screening for trisomy 21 has higher sensitivity, lower false positive rate, and higher positive predictive value than standard screening. What does this study add? Cohort study of low risk women who received results of both standard and cfDNA screening with outcome of pregnancies collected in all cases. Direct demonstration of the reduction of invasive testing based on cfDNA screening. Demonstration of limited clinical utility of nuchal translucency measurement in women with a negative cfDNA test result.