title: Noninvasive glucose measurement by monitoring of scattering coefficient during oral glucose tolerance tests. Non-Invasive Task Force.
abstract: BACKGROUND
  Continuous glucose monitoring by means of optical glucose sensors would allow patients with diabetes to check their metabolic control to their convenience. In an earlier study, we showed that noninvasive glucose monitoring is feasible for rapid changes in blood glucose by means of measuring the scattering coefficient of human skin. In this study, we investigated whether also slower changes in blood glucose, this time induced by an oral glucose load, can also be monitored by this approach.
  
  
  METHODS
  Five healthy subjects and 13 patients with type 2 diabetes have been given a 75-g oral glucose load. Portable noninvasive systems were used to measure the skin tissue scattering coefficient. For this purpose, two optical sensor heads were attached directly to the skin of each volunteer. Light was applied to the skin and the reflected light intensity was registered.
  
  
  RESULTS
  In 8 of 10 measurements, correlation of changes in scattering coefficient with changes in glycemia was acceptable. In 19 of 26 measurements (73%) of patients with type 2 diabetes the observed changes in the scattering coefficient also correlated in acceptable manner. The accordance between the simultaneous measurements of the two sensor heads was acceptable in 13 of 18 volunteers and patients studied. There were virtually no differences in the quality of the measurements between healthy volunteers and patients with diabetes.
  
  
  CONCLUSIONS
  This study shows that also slow changes in blood glucose induced by an oral glucose load can be monitored by registration of scattering coefficient changes. It remains to be elucidated why this has not been possible in all experiments.
authors.affiliation: Profil Institute for Metabolic Research GmbH, Neuss, Germany. Lutz.Heinemann@profil-research.de
authors.forename: L
authors.initials: L
authors.lastname: Heinemann
authors.forename: U
authors.initials: U
authors.lastname: Krämer
authors.forename: H M
authors.initials: HM
authors.lastname: Klötzer
authors.forename: M
authors.initials: M
authors.lastname: Hein
authors.forename: D
authors.initials: D
authors.lastname: Volz
authors.forename: M
authors.initials: M
authors.lastname: Hermann
authors.forename: T
authors.initials: T
authors.lastname: Heise
authors.forename: K
authors.initials: K
authors.lastname: Rave
mesh_terms: D000328:Adult; D000465:Algorithms; D015374:Biosensing Techniques; D001786:Blood Glucose / Q000032:analysis*; D015190:Blood Glucose Self-Monitoring / Q000295:instrumentation / Q000379:methods*; D003924:Diabetes Mellitus, Type 2 / Q000097:blood*; D005110:Extracellular Space / Q000737:chemistry*; D005947:Glucose / Q000032:analysis*; D005951:Glucose Tolerance Test / Q000295:instrumentation / Q000379:methods*; D006801:Humans; D008027:Light; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000379:methods*; D012016:Reference Values; D012542:Scattering, Radiation; D012867:Skin; D012881:Skin Temperature
chemical_list: D001786:Blood Glucose; D005947:Glucose