Comment on “Validation and Proposal of a Clinical Intervention Cutoff in Fetal Scalp Blood for the Point-of-Care-Lactate Meter StatStrip®2”

Fetal scalp blood sampling (FBS) with cardiotocography is a recognized method of assessing whether a fetus is getting enough oxygen during labor. Point-of-care (POC) devices used to measure lactate provide results within seconds, making them useful in the clinical setting. However, the calibration for each device varies, requiring its own safety cutoff level for ruling out fetal acidosis. The StatStrip® Lactate is a POC lactate meter that has been clinically validated with a 5.2 mmol/L lactate cutoff as the threshold for clinical intervention. However, it will no longer be available in Europe due to the new In-Vitro Diagnostics Regulations. Instead, the newer StatStrip® Lactate 2 (SSL2) has been launched. The aim of this study was to validate the SSL2 for fetal blood analysis and determine the cutoff for clinical decision-making. This was a prospective, observational analysis conducted in 3 maternity clinics in Sweden and Denmark between August 2024 and February 2025. Included were normal, term, singleton pregnancies, in which FBS was indicated because of nonreassuring CTG patterns during labor. Excluded were pregnancies that were contraindicated for FBS. The first drop of fetal scalp blood was measured using the SSL1 device (independent variable), and the same drop was analyzed up to 3 times with the SSL2 device (dependent variable). Linear regression was used to assess the correlation and derive the conversion equations to determine the intervention cutoff. A total of 549 paired lactate concentration measurements were included in the analysis. There was a positive correlation between SSL1 and SSL2 ( r =0.943, P <0.001). Using the conversion equation SSL2=(1.4 × SSL1) − 0.28, the established cutoff for SSL1 of ≥5.2 mmol/L corresponded to an SSL2 cutoff of ≥7.0 mmol/L (95% CI, 5.68-8.36). A secondary analysis using only cases with SSL1 values ≥4.2 mmol/L confirmed the SSL2 cutoff. The SSL2 lactate concentration values were 35% higher than those of SSL1. In conclusion, the SSL2 device showed a strong correlation with the previously established SSL1 device, suggesting that the newer device is reliable for FBS measurement. The suggested intervention cutoff for the SSL2 is 7.0 mmol/L. (Summarized from Gellert S, Norrestam S, Tidstedt A, et al. Validation and proposal of a clinical intervention cutoff in fetal scalp blood for the point-of-care-lactate meter StatStrip®2. Acta Obstet Gynecol Scan d . 2025;104:2273-2281. doi:10.1111/aogs.70080).