Objectives Pre-eclampsia is a major cause of maternal death. Placental growth factor (PlGF) testing improves time-to-diagnosis and outcomes. We evaluated two novel, whole blood, point-of-care (POC) PlGF tests (RONIATM and Lepzi® Quanti PlGF) in a low-resource setting, for prediction of adverse outcomes. Study Design A prospective observational cohort study in hypertensive pregnant women, 24-36+6 weeks' gestation, at a tertiary maternity hospital in Sierra Leone. Methods Eligible, consented women underwent RONIATM and/or Lepzi® Quanti PLGF testing; results were concealed. Optimal rule-out and rule-in thresholds were determined for prediction of predefined maternal (maternal death, eclampsia) and perinatal (stillbirth, termination pre-viability, neonatal death before discharge) composite outcomes. Sensitivity, specificity, negative (NPV) and positive predictive values were determined. Results Analysis was performed on women with complete outcomes: RONIATM n=488 and Lepzi® Quanti PlGF n=140. Optimal thresholds were <60pg/mL or <90pg/mL (rule-out) and <20pg/mL or <12pg/mL (rule-in) for RONIATM and Lepzi® Quanti PlGF respectively. For tests performed <34 weeks' gestation, RONIATM PlGF <60pg/mL had high sensitivity, 94.9% (95%CI 82.7-99.4%) and NPV, 94.6% (95%CI 81.8-99.3%) for maternal outcomes, with sensitivity, 100% (95%CI 95.8-100.0%) and NPV, 100% (95%CI 90.5-100%) for the perinatal composite. Lepzi® Quanti PlGF < 90pg/mL had 100% sensitivity and NPV for all predefined maternal and neonatal outcomes. Performance reduced slightly at later gestations. Conclusions Whole blood POC-PlGF measurement demonstrates accurate rule-out performance of two novel devices for serious outcomes, with potential for individualised risk stratification in low-resource settings.

The authors have declared no competing interest.

N/A

This work was supported by the UK Medical Research Council (MR/T038594/1) and NIHR (NIHR133232). No additional funding was received.

I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.

Yes

The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

The study was approved by Kings College London Research Ethics Committee (RECSM22/23-22669) and Sierra Leone Ethics and Scientific Review Committee (10/03/2022).

I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals.

Yes

I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).

Yes

I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable.

Yes

The dataset will be available to appropriate academic parties on request to the chief investigator (AHS) in accordance with the data sharing policies of King's College London.