title: Feasibility of an Orthogonal Redundant Sensor incorporating Optical plus Redundant Electrochemical Glucose Sensing.
abstract: Orthogonal redundancy for glucose sensing (multiple sensing elements utilizing distinct methodologies) may enhance performance compared to nonredundant sensors, and to sensors with multiple elements utilizing the same technology (simple redundancy). We compared the performance of a prototype orthogonal redundant sensor (ORS) combining optical fluorescence and redundant electrochemical sensing via a single insertion platform to an electrochemical simple redundant sensor (SRS).
  
  
  
  Twenty-one adults with type 1 diabetes wore an ORS and an SRS concurrently for 7 days. Following sensor insertion, and on Day 4 with a standardized meal, frequent venous samples were collected for reference glucose measurement (laboratory [YSI] and meter) over 3 and 4 hours, respectively. Between study visits reference capillary blood glucose testing was undertaken. Sensor data were processed prospectively.
  
  
  
  ORS mean absolute relative difference (MARD) was (mean ± SD) 10.5 ± 13.2% versus SRS 11.0 ± 10.4% (P = .34). ORS values in Clarke error grid zones A and A+B were 88.1% and 97.6%, respectively, versus SRS 86.4% and 97.8%, respectively (P = .23 and P = .84). ORS Day 1 MARD (10.7 ± 10.7%) was superior to SRS (16.5 ± 13.4%; P < .0001), and comparable to ORS MARD for the week. ORS sensor survival (time-averaged mean) was 92.1% versus SRS 74.4% (P = .10). ORS display time (96.0 ± 5.8%) was equivalent to SRS (95.6 ± 8.9%; P = .87).
  
  
  
  Combining simple and orthogonal sensor redundancy via a single insertion is feasible, with accuracy comparing favorably to current generation nonredundant sensors. Addition of an optical component potentially improves sensor reliability compared to electrochemical sensing alone. Further improvement in optical sensing performance is required prior to clinical application.
authors: Department of Medicine, St Vincent's Hospital, University of Melbourne, Melbourne, Australia Department of Endocrinology & Diabetes, St Vincent's Hospital Melbourne, Melbourne, Australia.
authors: Sybil A
authors: SA
authors: McAuley
authors: Medtronic Diabetes, Northridge, CA, USA.
authors: Tri T
authors: TT
authors: Dang
authors: Department of Medicine, St Vincent's Hospital, University of Melbourne, Melbourne, Australia.
authors: Jodie C
authors: JC
authors: Horsburgh
authors: Medtronic Diabetes, Northridge, CA, USA.
authors: Anubhuti
authors: A
authors: Bansal
authors: Department of Medicine, St Vincent's Hospital, University of Melbourne, Melbourne, Australia Department of Endocrinology & Diabetes, St Vincent's Hospital Melbourne, Melbourne, Australia.
authors: Glenn M
authors: GM
authors: Ward
authors: Medtronic Diabetes, Northridge, CA, USA.
authors: Sarkis
authors: S
authors: Aroyan
authors: Department of Medicine, St Vincent's Hospital, University of Melbourne, Melbourne, Australia Department of Endocrinology & Diabetes, St Vincent's Hospital Melbourne, Melbourne, Australia NHMRC Clinical Trials Centre, University of Sydney, Sydney, Australia.
authors: Alicia J
authors: AJ
authors: Jenkins
authors: Department of Medicine, St Vincent's Hospital, University of Melbourne, Melbourne, Australia Department of Endocrinology & Diabetes, St Vincent's Hospital Melbourne, Melbourne, Australia.
authors: Richard J
authors: RJ
authors: MacIsaac
authors: Medtronic Diabetes, Northridge, CA, USA.
authors: Rajiv V
authors: RV
authors: Shah
authors: Department of Medicine, St Vincent's Hospital, University of Melbourne, Melbourne, Australia Department of Endocrinology & Diabetes, St Vincent's Hospital Melbourne, Melbourne, Australia dno@unimelb.edu.au.
authors: David N
authors: DN
authors: O'Neal
mesh_terms: D000328:Adult; D001786:Blood Glucose / Q000032:analysis*; D015190:Blood Glucose Self-Monitoring / Q000295:instrumentation*; D002138:Calibration; D003922:Diabetes Mellitus, Type 1 / Q000097:blood*; D055664:Electrochemical Techniques; D004867:Equipment Design; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018670:Monitoring, Ambulatory / Q000295:instrumentation
chemical_list: D001786:Blood Glucose
keywords: accuracy; continuous glucose monitoring; optical fluorescence; orthogonal redundancy; reliability; sensor redundancy