Table 2:

Overall and modality-specific performance of a universal and publicly funded prenatal screening program for trisomies 21 (T21) and 18 (T18)

VariableOverallMMScfDNA
T21T18T21T18T21T18
Sensitivity (95% CI)89.94 (87.50–92.05)80.47 (74.53–85.54)86.25 (83.19–88.95)76.79 (69.66–82.94)99.78 (98.77–99.99)94.44 (88.30–97.93)
Specificity (95% CI)98.76 (98.72–98.81)99.89 (99.88–99.91)94.99 (94.91–95.08)99.76 (99.74–99.78)99.81 (99.74–99.87)99.95 (99.91–99.97)
PPV (95% CI)17.26 (16.06–18.51)39.23 (34.64–43.96)3.94 (3.61–4.29)17.79 (15.08–20.78)91.99 (89.21–94.24)90.27 (83.25–95.04)
NPV (95% CI)99.97 (99.96–99.98)99.98 (99.98–99.99)99.97 (99.96–99.97)99.98 (99.98–99.99)> 99.99 (99.97–100.00)99.97 (99.94–99.99)
  • Note: cfDNA = cell-free fetal DNA screening, CI = confidence interval, MMS = multiple marker screening, NPV = negative predictive value, PPV = positive predictive value.