Accuracy of the Enlite 6-day glucose sensor with guardian and Veo calibration algorithms

Diabetes Technol Ther. 2012 Mar;14(3):225-31. doi: 10.1089/dia.2011.0199. Epub 2011 Dec 6.

Abstract

Objective: This study investigates the accuracy of a newly developed, next-generation subcutaneous glucose sensor, evaluated for 6-day use.

Research design and methods: Seventy-nine subjects (53 men, 26 women) with type 1 diabetes and 18 subjects (14 men, four women) with type 2 diabetes completed a three-center, prospective, sensor accuracy study. The mean age for the group was 42.2±15.0 years (mean±SD), ranging from 18 to 71 years, with a mean glycosylated hemoglobin level of 7.6±1.5%, ranging from 5.5% to 14%. Subjects wore Enlite™ sensors (Medtronic Diabetes, Northridge, CA) in the abdominal and buttocks region for two separate 7-day periods and calibrated with a home-use blood glucose meter. Subjects participated in an in-clinic testing day where frequent sampled plasma glucose samples were acquired every 15 min for 10 h. Sensor data was retrospectively processed with Guardian(®) REAL-Time (Medtronic) and Paradigm(®) Veo™ (Medtronic) calibration routines, and accuracy metrics were calculated for each algorithm and sensor location. Physiological time lag for each measurement site was calculated.

Results: Based on 6,404 plasma-sensor glucose paired points, the Enlite sensor with Veo calibration algorithm produced a mean absolute relative difference of 13.86% with 97.3% of points within the A+B zones of the Clarke error grid. Threshold-only alarms detected 90.1% of hypoglycemia and 90% of hyperglycemia. Mean time lag measured at the abdominal region was 7.94±6.48 min compared with 11.70±6.71 min (P<0.0001) at the buttocks area.

Conclusions: The Enlite sensor accurately measures glucose when compared with gold standard laboratory measurements over its 6-day use. Sensors placed in the buttocks region exhibited greater time lags than sensors placed in the abdomen.

Publication types

  • Multicenter Study

MeSH terms

  • Abdomen
  • Adult
  • Aged
  • Algorithms
  • Biosensing Techniques / instrumentation*
  • Blood Glucose / metabolism*
  • Blood Glucose Self-Monitoring / instrumentation*
  • Buttocks
  • Calibration
  • Diabetes Mellitus, Type 1 / drug therapy
  • Diabetes Mellitus, Type 1 / metabolism*
  • Diabetes Mellitus, Type 2 / drug therapy
  • Diabetes Mellitus, Type 2 / metabolism*
  • Female
  • Humans
  • Hyperglycemia / diagnosis
  • Hyperglycemia / metabolism
  • Hypoglycemia / diagnosis
  • Hypoglycemia / metabolism
  • Hypoglycemic Agents / administration & dosage*
  • Insulin Infusion Systems*
  • Male
  • Materials Testing
  • Middle Aged
  • Prospective Studies
  • Sensitivity and Specificity
  • Time Factors

Substances

  • Blood Glucose
  • Hypoglycemic Agents