Determination of Time Delay between Blood and Interstitial Adipose Tissue Glucose Concentration Change by Microdialysis in Healthy Volunteers

For the development and use of subcutaneous glucose sensors it is important to know the time lag between changes in blood glucose and subcutaneous interstitial glucose concentration. To determine the time lag we inserted a microdialysis probe into the abdominal subcutaneous adipose tissue of healthy volunteers (n =19) and performed oral glucose tolerance tests (n=39) over a 7-day period. After correction for the microdialysis system time lag, we compared the change in dialysate glucose concentration with the capillary blood glucose concentration. We found no significant delay time between a change in capillary blood glucose concentration and subcutaneous interstitial fluid glucose concentration using the Mann-Whitney test. The substantial interindividual variation of glucose recovery and the changing recovery in time makes it difficult to draw unambiguous conclusions about the exact physiological time lag. Based on the present experimental findings and theoretical calculations of glucose transport in adipose tissue, the physiological lag time is short and negligible compared to the system delay time of a glucose sensor.