Which angiogenic biomarker ratio has the highest diagnostic accuracy for differentiating pre-eclampsia from other hypertensive disorders in pregnancy and is used clinically for 'rule-out' at >36 weeks gestation?
- A sFlt-1 to PlGF ratio >85 rules in and <38 rules out pre-eclampsia within 1 week
- B PlGF to sFlt-1 ratio <0.5 rules in and >2 rules out pre-eclampsia within 4 weeks
- C sFlt-1 to PlGF ratio >85 rules in and <38 rules out pre-eclampsia, with >110 at >34 weeks indicating imminent delivery ✓
- D Endoglin to PlGF ratio >10 provides the best discrimination and predicts adverse outcomes within 2 weeks
Explanation
The sFlt-1:PlGF (soluble FMS-like tyrosine kinase-1 to placental growth factor) ratio is the validated angiogenic biomarker for pre-eclampsia. A ratio <38 effectively rules out pre-eclampsia for 1 week (negative predictive value >99%); a ratio >85 before 34 weeks or >110 at 34–37 weeks rules it in and predicts imminent delivery. Option A correctly states some thresholds but omits the gestational-age-specific cut-off of >110 after 34 weeks, which is clinically important. Option B inverts the ratio incorrectly (it's sFlt-1/PlGF, not PlGF/sFlt-1). Soluble endoglin (option D) co-elevates with sFlt-1 in pre-eclampsia but is not the primary validated clinical tool.
Reference: Williams Obstetrics, 26th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.