Are we ready for widespread implementation of lactate POCT in fetal blood sampling? An analytical and clinical verification of the novel statstrip POCT analyzer

Objectives

Currently, pH values are used in fetal scalp blood sampling as a parameter to rule out fetal distress during the delivery. Due to a high number of pre-analytical errors in pH measurements, lactate measurement is already extensively examined as an alternative. Our objectives were to confirm the analytical performance of the StatStrip lactate POCT analyzer and to compare pH and lactate as a marker of fetal distress.

Design

and methods: Fetal blood scalp, umbilical and arterial blood test results (n = 100) were analyzed to compare the current POC blood gas analyzer including lactate (iSTAT-1) with the new POCT analyzer (StatStrip) to test the analytical performance. Furthermore, in all fetal scalp blood tests with a lactate en pH measurement from 2021 to 2023, clinical delivery data was collected to perform a clinical verification.

Results

The lactate concentration on the StatStrip analyzer correlated well with the iSTAT-1 (Pearson's r ≥ 0.95). 73 Fetal scalp blood tests showed 18% discrepant results when comparing pH and lactate with regard to fetal distress and consequent delivery intervention. Lactate showed more false positive results than pH (4 versus 1), but no false negatives as opposed to pH (0 versus 1).

Conclusions

The lactate Statstrip and iSTAT-1 POCT analyzers were analytically equivalent. The clinical verification study showed that lactate is a good predictor of fetal distress, although more false positive results were found in our limited dataset. However, unnecessary interventions due to failed pH measurements might be prevented when a lactate measurement is introduced.