Table 3 Performance of two screening tests with traditional contingent screening strategy
From: A new contingent screening strategy increased detection rate of trisomy 21 in the first trimester
Risk stratification | Serum biochemical screening | Combined first-trimester screening | ||||
|---|---|---|---|---|---|---|
n(%) | Trisomy 21 (%) | OAPR | n(%) | Trisomy 21 (%) | OAPR | |
high risk (risk ≥ 1/270) | 1,874 (5.31%) | 29 (61.70%) | 1:64 | 875 (2.50%) | 34 (72.34%) | 1:26 |
intermediate risk (1/1,000 ≤ risk < 1/270) | 5,029 (14.24%) | 9 (19.15%) | 1:558 | 1,748 (4.99%) | 6 (12.77%) | 1:291 |
low risk (risk < 1/1,000) | 28,405 (80.45%) | 9 (19.15%) | 32,403 (92.51%) | 7 (14.89%) | ||