Table 2.

Sensitivities, specificities, and positive predictive values for the high-risk NIPT cases

	Trisomy 21	Trisomy 18	Trisomy 13	Monosomy X
Cases (n)	117	34	23	13
Cases with follow-up [n (%)]	96 (82.1)	23 (67.6)	15 (65.2)	10 (76.9)
Sensitivity [% (n/N; 95% CI)]	98.89 (89/90; 93.96–99.97)	> 99.99 (19/19; 82.35–100)	> 99.99 (9/9; 66.37–100)	> 99.99 (5/5; 47.82–100)
Specificity [% (n/N; 95% CI)]	99.73 (2566/2573; 99.44–99.89)	99.84 (2496/2500; 99.59–99.96)	99.76 (2486/2492; 99.48–99.91)	99.80 (2482/2487; 99.53–99.93)
PPV [% (n/N)]	92.7 (89/96)	82.6 (19/23)	60.0 (9/15)	50.0 (5/10)
Theoretical lower PPV [% (n/N)]	76.1 (89/117)	55.9 (19/34)	39.1 (9/23)	38.5 (5/13)
Theoretical upper PPV [% (n/N)]	94.0 (110/117)	88.2 (30/34)	73.9 (17/23)	61.5 (8/13)