() Cohort III-2 216 Aim: to determine the positive predictive The PPV for cfDNA were as follows: 93% for (PPV) of noninvasive prenatal screening trisomy (T)21 (n=99; 95%CI 86-97.1%), 58% for (NIPS) for various aneuploidies based on T18 (n=24; 95%CI 36.6-77.9%), 45% for T13 cases referred for follow-up cytogenetic (n=11; 95% CI 16.7-76.6%), 23% for testing. Secondarily, to determine the monosomy X (n=26; 95% CI 9-43.6%), and (FN) rate for those cases with a 67% for XXY (n=6; 95% CI, 22.3-95.7%). negative NIPS result. Of the 26 cases referred for follow-up Setting: United States cytogenetics after a negative cfDNA result, 1 (4%) was false negative (T13). Two cases of Pregnancies at high-risk of fetal Population: triploidy, a very serious condition but one aneuploidy not claimed to be detectable by the test Methods: We compared the cytogenetic providers, were among those classified as findings (primarily from chromosome true negatives. analysis) from 216 cases referred to our T21, trial has the highest prevalence of all laboratories with either a positive or aneuploidies, demonstrated a high negative NIPS result, and classified NIPS rate, resulting in a high PPV. results as true positive, false positive, true However, the other aneuploidies, with their negative, or FN. Diagnostic cytogenetic lower prevalence, displayed relatively high testing was performed on the following false-positive rates and, therefore, lower tissue types: amniotic fluid (n = 137), PPV. Patients and physicians must fully chorionic villi (n = 69), neonatal blood (n=6), understand the limitations of this screening and products of conception (n = 4). test and the need in many cases to follow Detection of trisomies 21, 18, 13, Outcomes: up with appropriate diagnostic testing to monosomy X, XXY obtain an accurate diagnosis.
() Cohort III-2 216 Aim: to determine the positive predictive (PPV) of noninvasive prenatal screening (NIPS) for various aneuploidies based on cases referred for follow-up cytogenetic testing. Secondarily, to determine the (FN) rate for those cases with a negative NIPS result. Setting: United States Population: Pregnancies at high-risk of fetal aneuploidy Methods: We compared the cytogenetic findings (primarily from chromosome analysis) from 216 cases referred to our laboratories with either a positive or negative NIPS result, and classified NIPS results as true positive, false positive, true negative, or FN. Diagnostic cytogenetic testing was performed on the following tissue types: amniotic fluid (n = 137), chorionic villi (n = 69), neonatal blood (n=6), and products of conception (n = 4). Outcomes: Detection of trisomies 21, 18, 13, monosomy X, XXY The PPV for cfDNA were as follows: 93% for trisomy (T)21 (n=99; 95%CI 86-97.1%), 58% for T18 (n=24; 95%CI 36.6-77.9%), 45% for T13 (n=11; 95% CI 16.7-76.6%), 23% for monosomy X (n=26; 95% CI 9-43.6%), and 67% for XXY (n=6; 95% CI, 22.3-95.7%). Of the 26 cases referred for follow-up cytogenetics after a negative cfDNA result, 1 (4%) was false negative (T13). Two cases of triploidy, a very serious condition but one not claimed to be detectable by the test providers, were among those classified as true negatives. T21, has the highest prevalence of all aneuploidies, demonstrated a high rate, resulting in a high PPV. However, the other aneuploidies, with their lower prevalence, displayed relatively high false-positive rates and, therefore, lower PPV. Patients and physicians must fully understand the limitations of this screening test and the need in many cases to follow up with appropriate diagnostic testing to obtain an accurate diagnosis. trial
cfDNA%20testing%20evidence%20evaluation%2016May17.docx