Objective:
To evaluate the diagnostic performance of the COBAS Roche placental growth factor (PlGF) thresholds and the sFlt-1/PlGF ratio in predicting the need for birth due to placental dysfunction within short-term timeframes.
Methods:
A single centre retrospective analysis was undertaken for singleton pregnancies which had sFlt-1/PlGF ratio testing (Roche) between 20 weeks’ gestation and delivery between December 2020 and December 2022. The diagnostic performance for the outcome of delivery due to preeclampsia of PlGF >100 pg/mL, PlGF >150 pg/mL, and sFlt-1/PlGF ratio <38 was assessed within <1 week and between 1-4 weeks. Biomarker diagnostic metrics including Sensitivity (Sens), Specificity (Spec) and negative predictive value (NPV) were evaluated using R to generate receiver operator characteristic curves (ROC).
Results:
Of 1637 women, 1640 consecutive pregnancies were analysed. Comparative diagnostic accuracies were summarised (Table 1).
|
Timeframe and Metrics |
|
PlGF >150 |
PlGF >100 |
PlGF/sFlt-1 <38 |
|
<1 week |
NPV |
0.78 |
0.71 |
0.86 |
|
|
Sens |
0.8 |
0.58 |
0.86 |
|
|
ROC AUC |
0.75 (95%CI 0.71-0.79) |
|
0.83 (95%CI 0.80-0.86) |
|
1-4 weeks |
NPV |
0.9 |
0.82 |
0.88 |
|
|
Sens |
0.79 |
0.51 |
0.7 |
|
|
ROC AUC |
0.80 (95%CI 0.76-0.85) |
|
0.84 (95%CI 0.81-0.88) |
Optimal cutoff for PlGF to predict the development of preeclampsia in women delivering within 1 week was 112 (Sens 66.4%, Spec 73.4%, AUC 0.75; 95%CI: 0.70-0.79), and 136 (Sens 74.9%, Spec 69.5%, AUC 0.78; 95%CI: 0.75-0.81) for delivery within 1-4 weeks.
Conclusion:
Although a PlGF cutoff of >150 appears to have better NPV compared to >100, the sFlt-1/PlGF ratio <38 remains diagnostically superior at <1 week and 1-4 weeks.