() Cohort III-2 143,051 Aim: To compare the number and types of If cfDNA testing for Down syndrome had study chromosome anomalies prenatally replaced Down syndrome screening tests in diagnosed and the number of invasive 2006 and 2007, in Victoria, there would have procedures between current prenatal been 25 (7%) additional Down syndrome testing pathways (a combination of first or diagnosed, a 28% reduction in detection of second trimester screening plus ultrasound chromosomal anomalies. Specifically, 56% and/or diagnostic testing) and a pathway non-Down syndrome chromosome where cfDNA testing replaces Down anomalies would no longer detected syndrome screening tests. (including trisomy 13, trisomy 18, sex chromosome anomalies, balanced and Setting: Victoria, Australia unbalanced rearrangements, polyploidy, Population: women participating in prenatal and mosaic results). diagnostic testing With the inclusion of trisomy 13, trisomy 18, Methods: Numbers and of chromosome and sex chromosome aneuploidy in the anomalies for each referral category were cfDNA panel, the number of missed extracted from prenatal diagnostic testing anomalies would decrease to 11%. reports routinely collected in Victoria, There would have been 6,896 (84%) fewer Australia, in 2006 and 2007. These data were invasive procedures with cfDNA testing for then applied to the proposed Down syndrome; 83% fewer with an implementation strategy. aneuploidy panel.
() Cohort study III-2 143,051 Aim: To compare the number and types of chromosome anomalies prenatally diagnosed and the number of invasive procedures between current prenatal testing pathways (a combination of first or second trimester screening plus ultrasound and/or diagnostic testing) and a pathway where cfDNA testing replaces Down syndrome screening tests. Setting: Victoria, Australia Population: women participating in prenatal diagnostic testing Methods: Numbers and of chromosome anomalies for each referral category were extracted from prenatal diagnostic testing reports routinely collected in Victoria, Australia, in 2006 and 2007. These data were then applied to the proposed implementation strategy. If cfDNA testing for Down syndrome had replaced Down syndrome screening tests in 2006 and 2007, in Victoria, there would have been 25 (7%) additional Down syndrome diagnosed, a 28% reduction in detection of chromosomal anomalies. Specifically, 56% non-Down syndrome chromosome anomalies would no longer detected (including trisomy 13, trisomy 18, sex chromosome anomalies, balanced and unbalanced rearrangements, polyploidy, and mosaic results). With the inclusion of trisomy 13, trisomy 18, and sex chromosome aneuploidy in the cfDNA panel, the number of missed anomalies would decrease to 11%. There would have been 6,896 (84%) fewer invasive procedures with cfDNA testing for Down syndrome; 83% fewer with an aneuploidy panel.
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