() Cohort III-2 5,267 Aim: To assess the implementation of CFDNA screening was performed in 5,267 Study population into clinical practice utilising both women and as a first-line screening method may not be first- and second-line screening models. in 3,359 (63.8%). Detection rates were 100% generalisable to for trisomies 21 and 13 and 88% for the Australian Setting: Metropolitan private practices in trisomy 18. Of cases with known karyotypes, obstetric Australia the positive predictive value (PPV) of the community as Population: Singleton pregnancies in a test was highest for trisomy 21 (97.7%) and women were mixed risk population lowest for monosomy X (25%). predominantly Methods: cfDNA testing was offered as a older, Ultrasound detection of structural first-line screen, ideally followed by Caucasian and anomaly resulted in the detection of five combined first-trimester screening (cFTS), or from higher additional chromosome anomalies, two of as a second-line test following cFTS, socioeconomic which had high-risk cFTS results. particularly in those with a calculated risk groups For all chromosomal anomalies, cfDNA between 1:50 and 1:1000. alone detected 93.4%, cfDNA in a Outcomes: Detection of trisomies 21, 18 13, model detected 81.8% and cFTS alone sex chromosome aneuploidies and other detected 65.9% (P < 0.005). anomalies If had only had cFTS, the rate of invasive procedures would have been 5.5% higher (p<0.0001). Given the false-positive rate for all aneuploidies, cfDNA is an advanced screening test, rather than a diagnostic test.
() Cohort III-2 5,267 Aim: To assess the implementation of CFDNA into clinical practice utilising both first- and second-line screening models. Setting: Metropolitan private practices in Australia Population: Singleton pregnancies in a mixed risk population Methods: cfDNA testing was offered as a first-line screen, ideally followed by combined first-trimester screening (cFTS), or as a second-line test following cFTS, particularly in those with a calculated risk between 1:50 and 1:1000. Outcomes: Detection of trisomies 21, 18 13, sex chromosome aneuploidies and other anomalies screening was performed in 5,267 women and as a first-line screening method in 3,359 (63.8%). Detection rates were 100% for trisomies 21 and 13 and 88% for trisomy 18. Of cases with known karyotypes, the positive predictive value (PPV) of the test was highest for trisomy 21 (97.7%) and lowest for monosomy X (25%). Ultrasound detection of structural anomaly resulted in the detection of five additional chromosome anomalies, two of which had high-risk cFTS results. For all chromosomal anomalies, cfDNA alone detected 93.4%, cfDNA in a model detected 81.8% and cFTS alone detected 65.9% (P < 0.005). If had only had cFTS, the rate of invasive procedures would have been 5.5% higher (p<0.0001). Given the false-positive rate for all aneuploidies, cfDNA is an advanced screening test, rather than a diagnostic test. Study population may not be generalisable to the Australian obstetric community as women were predominantly older, Caucasian and from higher socioeconomic groups
cfDNA%20testing%20evidence%20evaluation%2016May17.docx