Point-of-Care Placental Growth Factor for Predicting Adverse Outcomes in Sierra Leone

BACKGROUND: PlGF (placental growth factor) concentrations are lower in preeclampsia, a major cause of maternal death; testing improves diagnosis and outcomes. We evaluated 2 novel, whole blood, point-of-care PlGF tests (RONIA and Lepzi Quanti) in a low-resource setting for predicting adverse outcomes. METHODS: A prospective observational cohort study in women with hypertension, 24 to 36 +6 weeks of gestation, Sierra Leone. Eligible women underwent concealed RONIA and Lepzi Quanti PLGF testing. Optimal rule-out and rule-in thresholds were determined for predicting maternal (death and eclampsia) and perinatal (stillbirth, termination previability, and neonatal death) composite outcomes. Sensitivity, specificity, negative predictive values, and positive predictive values were assessed. RESULTS: Analysis included women with RONIA (n=488) and Lepzi Quanti (n=140) PlGF tests. Optimal thresholds were >60 or >90 pg/mL (rule-out) and <20 or <12 pg/mL (rule-in) for RONIA and Lepzi Quanti, respectively. For tests <34 weeks, RONIA <60 pg/mL had high sensitivity and negative predictive value for ruling out maternal (94.9% and 94.6%) and perinatal (100%) composite outcomes. RONIA <20 pg/mL indicated higher risk (positive predictive values, 16.3% and 40.9% respectively). Lepzi Quanti <90 pg/mL had 100% sensitivity and negative predictive value for ruling out maternal and perinatal composites. Conversely, with Lepzi Quanti <12 pg/mL, nearly one-fourth and half of pregnancies experienced the maternal and perinatal composites (positive predictive values, 22.0% and 48.0%). Performance declined slightly at later gestations. CONCLUSIONS: Point-of-care PlGF testing shows accurate rule-out performance for serious outcomes, with potential for risk stratification in low-resource settings. For both tests, a minority of cases fell into an intermediate category, which would warrant increased surveillance to determine progress.