Point-of-care testing of capillary glucose in the exclusion and diagnosis of diabetes in remote Australia

Objectives: To determine the utility of point-of-care (POC) capillary blood glucose measurements in the diagnosis and exclusion of diabetes in usual practice in primary health care in remote areas.Design: Cross-sectional study comparing POC capillary glucose results with corresponding venous glucose levels measured in a reference laboratory.Participants: 200 participants aged 16-65 years enrolled: 198 had POC capillary glucose measurements; 164 also had acceptable venous glucose laboratory results.Setting: Seven health care sites in the Kimberley region of Western Australia from May to November 2006.Main outcome measures: Concordance and mean differences between POC capillary blood glucose measurement and laboratory measurement of venous blood glucose level; POC capillary blood glucose equivalence values for excluding and diagnosing diabetes, and their sensitivity, specificity and positive-predictive value.Results: The concordance between POC and laboratory results was high (rho = 0.93, P < 0.001). The mean difference in results was 0.48 mmol/L (95% Cl, 0.23-0.73; limits of agreement, -2.6 to 3.6 mmol/L). The POC capillary glucose equivalence values for excluding and diagnosing diabetes were < 5.5 mmol/L (sensitivity, 53.3%; specificity, 94.4%; positive-predictive value, 88.9%; for a venous value of < 5.5 mmol/L) and >= 12.2 mmol/L (sensitivity, 83.3%; specificity, 99.3%; positive-predictive value, 95.2%; for a venous value of >= 11.1 mmol/L), respectively. While the choice of glucometer and whether or not patients were fasting altered these results, they did not have a significant influence on the diagnostic utility of POC glucose measurement in this setting.Conclusion: POC capillary blood glucose analysers can be used as part of the process of diagnosing and excluding diabetes in remote rural communities using these locally established capillary equivalence values.