Diabetes Care, Vol 18, Issue 9 1266-1269, Copyright © 1995 by American Diabetes Association
Subcutaneous glucose concentration in humans. Real estimation and continuous monitoring
F Sternberg, C Meyerhoff, FJ Mennel, F Bischof and EF Pfeiffer
Institute of Diabetes-Technology, University of Ulm, Donau, Germany.
OBJECTIVE: To determine the real subcutaneous glucose concentration in
healthy volunteers to help in the development of new calibration methods
for subcutaneous glucosensors. RESEARCH DESIGN AND METHODS: We developed a
new method to estimate the real subcutaneous glucose concentration based on
the recirculation of phosphate-buffered saline (PBS) in a microdialysis
probe inserted into the subcutaneous tissue. Tissue glucose diffuses into
the probe until complete equilibration between the glucose concentration
outside and inside the microdialysis probe is achieved. Later, the glucose
content of the recirculated PBS is assessed in vitro. We applied the method
in 10 healthy volunteers under fasting state and during a hyperglycemic
clamp. In addition, we monitored the subcutaneous glucose with an
enzymatic-amperometric glucosensor combined with a microdialysis probe.
RESULTS: The subcutaneous glucose concentration measured by the
recirculation method was 72 +/- 6 and 78 +/- 6% of the blood glucose
measured in the fasting state and during the hyperglycemic clamps,
respectively. On the other hand, the glucosensor's signal correlated
significantly with the blood glucose. CONCLUSION: The recirculation method
estimated the real subcutaneous glucose concentration, opening the way to
develop new calibration procedures for subcutaneous glucosensors. However,
a suitable calibration procedure is still lacking.