Comparison of two reflectance photometers in the assessment of neonatal hypoglycaemia

To assess the accuracy and reliability of reflectance photometers in estimating blood glucose concentrations, two were assessed: the Ames Glucometer 3 (Bayer Diagnostics) with Glucofilm Test strips; and the Reflolux S (Boehringer Mannheim) with BM Test Glycemia 20-800 strips. These were compared with laboratory blood glucose estimations in 100 assays (50 comparisons for each machine, measuring the difference (d) between the glucose reading and the mean of the reflectance photometer and the laboratory value). The Ames Glucometer 3 (mean d = + 0.7 mmol/l, (SD 1.1) mmol/l) was less accurate than the Boehringer Reflolux S (mean d = 0.2 mmol/l, (SD (0.7) mmol/l). The range of error of both machines is wide (Ames 2 SD range + 2.9 mmol/l to -1.5 mmol/l true readings; Boehringer + 1.8 mmol/l to -1.2 mmol/l of true readings). Because of this, any reflectance photometer readings that are even slightly low should be checked with laboratory estimations. The clinical value of such machines is limited in infants with low blood glucose concentrations.