Time Lag of Glucose from Intravascular to Interstitial Compartment in Humans

  1. Rita Basu, M.D.
  1. #Department of Information Engineering University of Padova, Via Gradenigo 6A, 35131 Padova, Italy.
  2. $Dexcom Inc. 6340 Sequence Drive, San Diego, CA 92121.
  3. *Department of Health Sciences Research, Mayo College of Medicine, Rochester, MN 55905 Endocrine Research Unit, Joseph 5-194, Mayo Clinic, Rochester, MN 55905
  1. Corresponding Author: Rita Basu, E-Mail: basu.rita{at}mayo.edu

Abstract

The accuracy of continuous interstitial fluid glucose sensing is an essential component of current and emerging open and closed loop systems for type 1 diabetes. An important determinant of sensor accuracy is the physiological time lag of glucose transport from the vascular to the interstitial space. We have performed the first direct measurement of this phenomenon in 8 healthy subjects under overnight fasted condition. Microdialysis catheters were inserted into the abdominal subcutaneous space. After intravenous bolus administrations of glucose tracers, timed samples of plasma and interstitial fluid were collected sequentially and analyzed for tracer enrichments. After accounting for catheter dead space and assay noise, the mean time lag of appearance of tracer into the interstitial space after intravenous bolus was 5.3 to 6.2 minutes. We conclude that in the overnight fasted state in healthy adults, the physiological delay of glucose transport from the vascular to the interstitial space is 5-6 minutes. Physiological delay between blood glucose and interstitial fluid glucose should, therefore, not be an obstacle to sensor accuracy in overnight or fasting state closed loop systems of insulin delivery or open loop therapy assessment for type 1 diabetes.

  • Received July 22, 2013.
  • Accepted August 30, 2013.

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This Article

  1. Diabetes
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