Glucose monitoring by microdialysis: performance in a multicentre study

Aims  The aim of this study was to assess the performance of the Continuous Research Tool (CRT) in a multicentre clinical-experimental study. Methods  Three patient groups totalling 28 subjects with diabetes [group A 10 Type 1 (Ulm), group B 10 Type 1 (Neuss), group C eight Type 2 (Aarhus)] participated in this trial. Two CRT microdialysis probes were inserted in parallel in the abdominal subcutaneous tissue for 120 h in each subject. In subjects in group A, glucose excursions were induced on one study day and those in group B underwent a glucose clamp (eu-, hypo- or hyperglycaemic) on one study day. CRT data were calibrated once with a retrospective calibration model based on a run-in time of 24 h and three blood glucose measurements per day. Results  All analysable experiments, covering a broad range of blood glucose values, yielded highly accurate data for the complete experimental time with a mean relative absolute difference of 12.8 ± 6.0% and a predictive residual error sum of squares of 15.6 ± 6.3 (mean ± SD). Of all measurement results, 98.2% were in zones A and B of the error grid analysis. The average absolute differences were 1.14 mmol/l for Type 1 and 0.88 mmol/l for Type 2 diabetic patients. Relative absolute differences were 16.0% for Type 1 and 12.6% for Type 2 diabetic patients. Conclusions  These results demonstrate that this microdialysis system allows reliable continuous glucose monitoring in patients with diabetes of either type.