Near-patient testing of blood glucose using the Bayer Rapidlab 860 analyser in a regional neonatal unit

Abstract

Background: We evaluated the use of the glucose biosensor on the Bayer Rapidlab 860 (BR 860) blood gas analyser for neonates and compared it with two laboratory-based methods for measuring blood glucose using the Yellow Springs Instruments 2300 STAT PLUS (YSI) analyser and the Vitros 750 XRC (Vitros) analyser. Methods: Arterial, capillary and venous blood samples were taken from 50 neonates, and blood glucose was measured using all three instruments. Blood pH, PO2, haematocrit and plasma albumin data were also recorded. The effect of varying the degree of haemolysis and the haematocrit was examined using cord blood samples prepared in vitro. Results: Day-to-day imprecision of the BR 860 was 4·90% at a mean glucose concentration of 2·55 mmol/L ( n=60), compared with 3·03% at 2·33 mmol/L ( n=34) for the YSI and 2·64% at 3·52 mmol/L for the Vitros ( n=59). Using Deming regression, the BR 860 results correlated well with results produced on both the YSI ( r=0·962, n=47, P<0·001) and Vitros ( r=0·980, n=46, P<0·001) analysers. Bland-Altman difference plots showed that the BR 860 had a mean of the differences of 0·30 mmol/L compared with the YSI and 0·09 mmol/L compared with the Vitros. The Bland-Altman standard deviation of the differences was 0·46 mmol/L when the BR 860 was compared with the YSI and 0·31 mmol/L when the BR 860 was compared with the Vitros. No significant correlation was found between the BR 860 glucose measurements and haematocrit, degree of sample haemolysis, plasma albumin, blood pH or PO2. Conclusions: The BR 860 analyser provides neonatal blood glucose measurements in the clinical setting of a neonatal unit that compare well with results obtained using laboratory-based methods.