Point-of-care testing of HbA_1c and blood glucose in a remote Aboriginal Australian community

Objectives: To assess the accuracy of point-of-care (POC) measurements of capillary blood glucose and glycosylated haemoglobin (HbA_1c) levels in a remote Aboriginal community with high diabetes prevalence. Design: Cross-sectional study comparing POC capillary glucose and HbA_1c results with those from corresponding venous samples measured in a reference laboratory. Participants and setting: 152 residents aged 11-76 years (representing 76% of population aged over 11 years) had POC glucose measurement in November 2003; 88 with POC glucose level ≥ 5.0 mmol/L, or self-reported diabetes, had POC HbA_1c and laboratory glucose and HbA_1c measurements. Main outcome measures: POC fasting capillary levels of glucose (HemoCue Glucose 201 analyser, Medipac Scientific, Sydney) and HbA_1c (DCA 2000+ analyser, Bayer Australia, Melbourne); correlation and mean difference between capillary POC and venous blood laboratory measurements of glucose and HbA_1c. Results: Mean and median POC capillary glucose levels were 7.99 mmol/L and 6.25 mmol/L, respectively, while mean and median laboratory venous plasma glucose concentrations were 7.63 mmol/L and 5.35 mmol/L. Values for POC capillary HbA_1c and laboratory HbA_1c were identical: mean, 7.06%; and median, 6.0%. The correlation coefficient r for POC and laboratory results was 0.98 for glucose and 0.99 for HbA_1c. The mean difference in results was 0.36 mmol/L for glucose (95% Cl, 0.13-0.62; limits of agreement [LOA], -2.07 to 2.79 mmol/L; P = 0.007) and < 0.01% for HbA_1c (95% Cl, -0.07% to 0.07%; LOA, -0.66% to 0.66%; P = 0.95), respectively. Conclusions: POC capillary HbA_1c, testing, in particular, offers an accurate, practical, community-friendly way of monitoring diabetes in rural and remote clinical settings. POC capillary glucose results should be confirmed by a laboratory test of venous plasma if the results are likely to significantly influence clinical decisions.