A pilot study to evaluate a novel subcutaneous continuous glucose monitoring system in healthy Beagle dogs

Serial blood glucose measurements are currently regarded as the 'gold standard' for evaluating glycaemic control of canine diabetic patients. The aim of this study was to investigate a subcutaneous continuous glucose monitoring system based on microdialysis. Analyses were performed by taking interstitial glucose samples from two different anatomical regions (interscapular region [IR], thoracic region [TR]) in six healthy Beagle dogs during induced hypoglycaemia and hyperglycaemia, the feeding period and a period of stable glucose values. For comparison, plasma glucose concentration was measured simultaneously by a hexokinase-based automated chemistry analyser. The mean absolute differences ranged from 11.7 mg/dL (SD 23.5 mg/dL, TR) to 5.3 mg/dL (SD 19.2 mg/dL, IR) with a correlation of r=0.43-0.92 (P<0.01). Sensitivity for the detection of hypoglycaemia was 85.0% TR and 93.3% IR, and the specificity was 99.5% TR and 99.7% IR, respectively. In a modified Clarke error grid analysis, 99.3% TR and 99.7% IR of the values fell into zone A and B. Collapse of the microdialysis fibre was a recurrent problem although this was easily detectable by fluctuations in system pressure. The microdialysis system reflects physiological as well as induced variations in blood glucose in a valid manner.