Evaluation of a new critical-care medicine instrument for real-time electrolytes and blood gas measurements

Abstract

Background: Glucometry is an essential part of diabetes treatment, but so far, no standard quality control procedure verifying blood glucose meter results is available. In this study, we evaluated the analytical performance of eight glucose meters: GX and Esprit™ (Bayer Diagn.), MediSense® Card Sensor, ExacTech (MediSense®) with strips Selfcare™ (Cambridge Diagn), One Touch® Basic, One Touch® II, One Touch® Profile (Lifescan) and Glucotrend® (Boehringer Mannheim/Roche). Methods: The evaluation included within-run imprecision, linearity, comparison with the laboratory method and calculation of differences between individual glucometers. Results: Within-run imprecision ranged from 1.5% to 4.5%, linearity assessed as the correlation between measured and calculated glucose concentrations yielded r2 values from 0.97 to 0.981. Analytical bias of glucose concentration values obtained by the glucometry amounted from 0.14% to 16.9% of values measured by the laboratory method. Bias higher than 5% was found for One Touch® Basic, II and Profile meters (however, glucose concentrations in plasma obtained by the laboratory method One Touch® meters showed analytical bias from 3.0% to 8.8%). The regression analysis yielded slope values from 0.77 to 1.09 and r2 values from 0.86 to 0.98. The best correlations with the laboratory method were found for One Touch® Basic, II Profile, Glucotrend® and Esprit™ meters. The calculated differences between the individual glucose meters can constitute 0.02–1.49 mmol/l (0.96–26.9%) at glucose concentration 5.55 mmol/l, and 0.16–4.16 mmol/l (0.96–24.96%) at glucose concentration 16.67 mmol/l. Error grid analyses have shown that Glucometers One Touch® Basic and One Touch® Profile yielded all results in zone A (acceptable). The remaining glucometers yielded 1–7% of results in zones B (insignificant errors), C or D (lack of detection and treatment). Conclusions: All studied glucometers had both small deviation from laboratory reference values (<10%) and high concurrence with results obtained by the laboratory method.