Objective Determination of lactate in fetal scalp blood (FBS) during labor has been studied since the 1970s. The internationally accepted cut-off of >4.8mmol/L indicating fetal acidaemia is exclusive for the point-of-care device (POC) LactateProTM, which is no longer in production. The aim of this study was to present a new cut-off for scalp lactate based on neonatal outcomes with the use of StatstripLactate®/StatstripXpress® Lactate system, the only POC lactate meter designed for hospital use. Design Observational Study Setting January 2016 to March 2020 labouring women with an indication for FBS were prospectively included from seven Swedish and one Australian delivery unit. Population Inclusion criteria: singleton pregnancy, vertex presentation, ≥35+0 gestational weeks. Method Based on the optimal correlation between FBS lactate and cord pH/lactate, only cases with ≤25 minutes from FBS to delivery were included in the final calculations. Main outcome measures Metabolic acidosis in cord blood was defined as pH <7.05 plus BDecf >10 mmol/L and/or lactate >10 mmol/L. Results 3334 women were enrolled of which 799 were delivered within 25 minutes. The areas under the ROC curves (AUC) and corresponding optimal lactate cut-off values were as follows; metabolic acidosis AUC 0.87(95% CI:0.77-0.97), cut-off 5.7mmol/L; pH <7.0 AUC 0.83(95% CI:0.68-0.97), cut-off 4.6mmol/L; pH <7.05 plus BD ≥12mmol/L AUC 0.97(95% CI:0.92-1), cut-off 5.8mmol/L; Apgar score <7 at 5 minutes AUC 0.74(95% CI:0.63-0.86), cut-off 5.2mmol/L; and pH <7.10 plus composite neonatal outcome AUC 0.76(95% CI:0.67-0.85), cut-off 4.8mmol/L. Conclusions Suggested intervention threshold for fetal acidemia is scalp lactate of 5.2mmol/L using the StatstripLactate®/StatstripXpress®.