Table 4 Comparison of cell-free DNA test performance for trisomies 21, 18, 13 and SCAs between women at low and high risks for aneuploidya
From: Performance of cell free DNA as a screening tool based on the results of first trimester screening
Variable | High riska (n = 131) | Low risk (N = 1543) | P value (High vs. low risk) |
|---|---|---|---|
Trisomy 21 (n = 25) | |||
Sensitivity | 22/22 100% (85–100) | 3/3 100% (43.8–100) | 0.38 |
Specificity | 75/77 97.4% (91-99.5) | 1497/1498 99.9% (99.6–100) | 1.00 |
PPV | 22/24 91.6% (74-98.5) | 3/4 75% (30-98.7) | 0.002 |
NPV | 77/77 100% (95.1–100) | 1498/1498 100% (99.7–100) | 1.00 |
Prevalenceb | 16.79 | 0.19 | |
Likelihood ratio | 38.5 | 1498 | |
Trisomy 18 (n = 2) | |||
Sensitivity | 2/2 100 (17–100) | 0/0 - | 1.00 |
Specificity | 75/80 96.1% (89.3–98.9) | 1497/1499 99.8% (99.5–99.9) | 1.00 |
PPV | 2/7 40% (7.1–76.9) | 0/2 0 (0–82) | < 0.0001 |
NPV | 80/80 100% (95.1–100) | 1499/1499 100% (99.7–100) | 1 |
Prevalence | 1.52 | 0% | |
Likelihood ratio | 26 | - | |
Trisomy 13 (n = 2) | |||
Sensitivity | 2/2 100% (17–100) | 0/0 - | 0.4 |
Specificity | 75/76 98.6% (92.9–99.9) | 1497/1499 99.8% (99.5–99.9) | 1.00 |
PPV | 2/3 66.6% (11.8–98.3) | 0/2 0 (0–82) | < 0.001 |
NPV | 76/76 100% (95.1–100) | 1499/1499 100% (99.7–100) | 1.00 |
Prevalence | 1.52 | ||
Likelihood ratio | 76 | ||
SCAs (n = 6) | |||
Sensitivity | 6/6 100% (61–100) | 0/0 - | 0.002 |
Specificity | 75/93 80% (71–87) | 1497/1535 97.5% (96.6–98.2) | 1.00 |
PPV | 6/24 25% (12–45) | 0/38 0% (0-9.2) | 0.003 |
NPV | 93/93 100% (95.1–100) | 1535/1535 100% (99.7–100) | 1.00 |
Prevalence | 4.58 | ||
Likelihood ratio | 5.16 | ||
Trisomy 21,18, 13 & SCAs (n = 32) | |||
Sensitivity | 32/32 100% (89.3–100) | 3/3 100% (43.8–100) | < 0.0001 |
Specificity | 75/99 75.7% (66.4–83.2) | 1497/1540 97.2% (96.3–97.9) | 1.00 |
PPV | 32/56 57.1% (44.1–69.2) | 3/46 6.5% (2.2–17.5) | < 0.0001 |
NPV | 99/99 100% (95.1–100) | 1540/1540 100% (99.7–100) | 1.00 |
Prevalence | 24.42 | - | |
Likelihood ratio | 4.12 | - | |