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Observed positive predictive values by condition
| Variable | Trisomy 21 | Trisomy 18 | Trisomy 13 | Overall |
|---|---|---|---|---|
| AD/AS samples a | 85.5% (443/518) | 51.2% (130/254) | 41.0% (43/105) | 70.2% (616/877) |
| AD samples a | 92.8% (439/473) | 74.3% (127/171) | 50.0% (42/84) | 83.5% (608/728) |
Observed PPV based on cytogenetically confirmed cases.
