Table 4.
Biochemical screening diagnostic effectiveness for preterm delivery of a small for gestational age infant using absolute concentrations, and gestational age and maternal weight adjusted multiples of the median of sFLT1 and PlGF at 28 weeks of gestational age
| True positive/false positive | True negative/false negative | Positive likelihood ratio (95% CI) | Negative likelihood ratio (95% CI) | Sensitivity | Specificity | Positive predictive value | Negative predictive value | |
|---|---|---|---|---|---|---|---|---|
| Highest decile sFLT1/PlGF ratio | 19/377 | 3578/7 | 7·7 (6·0–9·9) | 0·30 (0·16–0·56) | 73·1% | 90·5% | 4·8% | 99·8% |
| Highest decile sFLT1 | 12/385 | 3570/14 | 4·7 (3·1–7·3) | 0·60 (0·42–0·85) | 46·2% | 90·3% | 3·0% | 99·6% |
| Lowest decile PlGF | 21/376 | 3579/5 | 8·5 (6·9–10·5) | 0·21 (0·10–0·47) | 80·8% | 90·5% | 5·3% | 99·9% |
| Highest decile sFLT1 (multiples of the median) | 13/385 | 3570/13 | 5·1 (3·5–7·6) | 0·55 (0·38–0·81) | 50·0% | 90·3% | 3·3% | 99·6% |
| Lowest decile PlGF (multiples of the median) | 20/377 | 3578/6 | 8·1 (6·4–10·2) | 0·26 (0·13–0·51) | 76·9% | 90·5% | 5·0% | 99·8% |
Multiples of the median were adjusted for the exact gestational age and maternal weight. The cutoff points of the highest decile were 6·90 for the sFLT1/PlGF ratio, 2788·5 for the sFLT1, and 1·83 for the sFLT1 multiples of the median. The cutoff points for the lowest decile of the PlGF were 252·7 and 0·48 for the PlGF multiples of the median. sFLT1=soluble fms-like tyrosine kinase 1. PlGF=placental growth factor.