Positive NIPT cases with confirmatory prenatal karyotype (n = 6238)

Trisomy

TP

(n)

FP

(n)

FN

(n)

Sensitivity %

(95% CI)

Specificity %

(95% CI)

PPV %

(95% CI)

Accuracy %

(95% CI)

Incidence %

(95% CI)

T21

54

1

0

100

(93.40 - 100)

99.98

(99.91 - 100)

98.18

(88.38 - 99.74)

99.98

(99.91 - 100)

0.87

(0.66 - 1.14)

T18

14

0

0

100

(76.84 - 100)

100

(99.94 - 100)

100

100

(99.94 - 100)

0.22

(0.12 - 0.38)

T13

2

0

0

100

(15.81 - 100)

100

(99.94 - 100)

100

100

(99.94 - 100)

0.03

(0.00 - 0.12)

XO

6

4

0

100

(54.07 - 100)

99.94

(99.84 - 99.98)

60

(36.03 - 79.98)

99.94

(99.84 - 99.98)

0.10

(0.04 - 0.21)

XXX

1

0

0

100

(2.5 - 100)

100

(99.94 - 100)

100

100

(99.94 - 100)

0.02

(0.00 - 0.09)

XXY

4

0

0

100

(39.76 - 100)

100

(99.94 - 100)

100

(39.58 - 100)

100

(99.94 - 100)

0.06

(0.02 - 0.16)

XYY

1

0

0

100

(2.5 - 100)

100

(99.94 - 100)

100

100

(99.94 - 100)

0.02

(0.00 - 0.09)

Total

82

5

0

100

(95.6 - 100)

99.92

(99.81 - 99.97)

94.25

(87.23 - 97.52)

99.92

(99.81 - 99.97)

1.31

(1.05 - 1.63)

All positive NIPT cases (n = 6238)

T21

117

1

0

100

(96.90 - 100)

99.99

(99.93 - 100)

99.15

(94.28 - 99.88)

99.99

(99.93 - 100)

1.50

(1.24 - 1.79)

T18

29

0

0

100

(88.06 - 100)

100

(99.95 - 100)

100

100

(99.95 - 100)

0.37

(0.25 - 0.54)

T13

9

0

0

100

(66.37 - 100)

100

(99.95 - 100)

100

100

(99.95 - 100)

0.12

(0.05 - 0.22)

XO

12

4

0

100

(73.54 - 100)

99.95

(99.87 - 99.99)

75

(52.97 - 88.88)

99.95

(99.87 - 99.99)

0.15

(0.08 - 0.27)

XXX

5

0

0

100

(47.82 - 100)

100

(99.95 - 100)

100

100

(99.95 - 100)

0.06

(0.02 - 0.15)

XXY

6

0

0

100

(54.07 - 100)

100

(99.95 - 100)

100

100

(99.95 - 100)

0.08

(0.03 - 0.17)

XYY

2

0

0

100

(15.81 - 100)

100

(99.95 - 100)

100

100

(99.95 - 100)

0.03

(0.00 - 0.09)

Total

180

5

0

100

(97.97 - 100)

99.93

(99.85 - 99.98)

97.30

(93.75 - 98.86)

99.94

(99.85 - 99.98)

2.30

(1.98 - 2.66)

Theoretical PPV Boundaries condition

Trisomy 21

(% (n))

Trisomy 18

(% (n))

Trisomy 13

(% (n))

XO

(% (n))

XXX

(% (n))

XXY

(% (n))

XYY

(% (n))

Total

(% (n))

Lower boundary

All unconfirmed cases considered as FP

46.15 (54/117)

48.28 (14/29)

22

(2/9)

50

(6/12)

20

(1/5)

66.67 (4/6)

50

(1/2)

45.56 (82/180)

Upper boundary

All unconfirmed cases considered as TP

99.15 (116/117)

100 (29/29)

90 (9/9)

66.7 (8/12)

100

(5/5)

100

(6/6)

100

(2/2)

97.22 (175/180)