title: Optimum subcutaneous glucose sampling and fourier analysis of continuous glucose monitors.
abstract: BACKGROUND
  The objective of this article was to focus on the application of harmonic decomposition to continuous glucose monitor (CGM) measurements. We show evidence of an attenuation of fast variations of interstitial glucose when compared to blood in type 1 diabetes mellitus (T1DM) and, using information theory, propose optimal sampling schedules associated with the use and study of CGMs.
  
  
  METHODS
  Using a cohort of 26 T1DM subjects, wearing two Navigator sensors for 1 to 3 days, we analyzed the frequency content of each glucose signal and derived across subject frequency cutoffs using discrete Fourier transform and common signal processing techniques.
  
  
  RESULTS
  We observed a significant difference in the frequency content of blood glucose compared to interstitial glucose in T1DM, providing evidence toward the existence of a diffusion process between blood and interstitial glucose, acting as a low-pass filter. Furthermore, we obtained a 15-minutes sampling schedule for optimal comparison of CGM values to blood reference.
  
  
  CONCLUSIONS
  Blood glucose and interstitial glucose have different dynamics, as shown by harmonic analysis, and these differences have consequences on advisable schedules for accuracy studies of CGMS.
authors.affiliation: University of Virginia Diabetes Technology Center, UVa Health System, Charlottesville, Virginia 22908-4888, USA. mb6nt@virginia.edu
authors.forename: Marc D
authors.initials: MD
authors.lastname: Breton
authors.forename: Devin P
authors.initials: DP
authors.lastname: Shields
authors.forename: Boris P
authors.initials: BP
authors.lastname: Kovatchev