Reliability of the point-of care analyzer “StatStrip® Xpress™” for measurement of fetal blood lactate

Objectives: Measurement of lactate in fetal blood is used to assess the degree of anaerobic metabolism. The technical difficulties in obtaining enough scalp blood for analysis by a bloodgas-analyzer advocates for the use of a point-of-care device. StatStrip®Xpress™ (SSX) has shown promising properties but needs further evaluation before implementation into fetal surveillance. Methods: Arterial/venous umbilical cord blood from 112 newborns were analyzed simultaneously with SSX and the reference method ABL800™. From 321 fetuses with abnormal heart rate scalp blood was sampled and analyzed repeatedly with SSX. Results: ABL800™ -lactate ranged from 1.9–13.3 mmol/L in arterial to 1.5–10.2 mmol/L in venous cord blood with excellent correlation to SSX (R ² = 0.95). SSX-values were lower compared to the reference method ranging from −0.79 mmol/L for low values to −1.68 mmol/L for high values. The mean CV for SSX-values in cord respectively scalp blood was: lactate ≤3 mmol/L 7.1% respectively 8.4%; lactate >3 mmol/L 3.8% respectively 6.8%. Repeated measurements of the same sample with SSX where without significant difference in cord/scalp blood (p = 0.11). Conclusion: SSX-lactate values were constantly lower but correlated excellent to the reference method. The reproducibility was good for cord and scalp blood. We suggest SSX as an attractive device for measurement of fetal lactate.