Table 3 Performance of NIPT to screen trisomies 21, 18 and 13 and sex chromosomal abnormalities
From: Performance of cell free DNA as a screening tool based on the results of first trimester screening
Variable | T21 | T18 | T13 | SCAs | T21/T18/T13/ SCAs |
|---|---|---|---|---|---|
Sensitivity | 25/25 100% (86.6–100) | 2/2 100% (17–100) | 2/2 100% (17–100) | 6/6 100% (61–100) | 35/35 100% (90–100) |
Specificity | 1646/1649 99.82% (99.5-99.95) | 1667/1672 99.68% (99.2-99.86) | 1669/1672 99.8% (99.4-99.95) | 1612/1668 96.5% (95.5–97.3) | 1639/1706 95.9% (94.8–96.7) |
PPV | 25/28 89% (72.8–96.3) | 2/7 28% (5–64) | 2/5 40% (7–77) | 6/62 9.6% (4.5–19.5) | 35/102 34% (25.8–43.9) |
NPV | 1649/1649 100% (99.76–100) | 1672/1672 100% (99.7–100) | 1672/1672 100% (99.7–100) | 1668/1668 100% (99.7–100) | 1639/1639 100% (99.7–100) |
Likelihood ratio | 525 | 315.4 | 525 | 29.07 | 24.46 |