title: The Performance and Usability of a Factory-Calibrated Flash Glucose Monitoring System.
abstract: BACKGROUND
  The purpose of the study was to evaluate the performance and usability of the FreeStyle(®) Libre™ Flash glucose monitoring system (Abbott Diabetes Care, Alameda, CA) for interstitial glucose results compared with capillary blood glucose results.
  
  
  METHODS
  Seventy-two study participants with type 1 or type 2 diabetes were enrolled by four U.S. clinical sites. A sensor was inserted on the back of each upper arm for up to 14 days. Three factory-only calibrated sensor lots were used in the study. Sensor glucose measurements were compared with capillary blood glucose (BG) results (approximately eight per day) obtained using the BG meter built into the reader (BG reference) and with the YSI analyzer (Yellow Springs Instrument, Yellow Springs, OH) reference tests at three clinic visits (32 samples per visit). Sensor readings were masked to the participants.
  
  
  RESULTS
  The accuracy of the results was demonstrated against capillary BG reference values, with 86.7% of sensor results within Consensus Error Grid Zone A. The percentage of readings within Consensus Error Grid Zone A on Days 2, 7, and 14 was 88.4%, 89.2%, and 85.2%, respectively. The overall mean absolute relative difference was 11.4%. The mean lag time between sensor and YSI reference values was 4.5±4.8 min. Sensor accuracy was not affected by factors such as body mass index, age, type of diabetes, clinical site, insulin administration, or hemoglobin A1c.
  
  
  CONCLUSIONS
  Interstitial glucose measurements with the FreeStyle Libre system were found to be accurate compared with capillary BG reference values, with accuracy remaining stable over 14 days of wear and unaffected by patient characteristics.
authors.affiliation: 1 AMCR Institute , Escondido, California.
authors.forename: Timothy
authors.initials: T
authors.lastname: Bailey
authors.affiliation: 2 Atlanta Diabetes Associates , Atlanta, Georgia .
authors.forename: Bruce W
authors.initials: BW
authors.lastname: Bode
authors.affiliation: 3 Diablo Clinical Research , Walnut Creek, California.
authors.forename: Mark P
authors.initials: MP
authors.lastname: Christiansen
authors.affiliation: 4 Rainier Clinical Research Center , Renton, Washington.
authors.forename: Leslie J
authors.initials: LJ
authors.lastname: Klaff
authors.affiliation: 5 Clinical Affairs, Abbott Diabetes Care , Alameda, California.
authors.forename: Shridhara
authors.initials: S
authors.lastname: Alva
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001786:Blood Glucose / Q000032:analysis*; D015190:Blood Glucose Self-Monitoring / Q000295:instrumentation* / Q000379:methods; D002138:Calibration; D002196:Capillaries; D003922:Diabetes Mellitus, Type 1 / Q000097:blood*; D003924:Diabetes Mellitus, Type 2 / Q000097:blood*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D015203:Reproducibility of Results; D013997:Time Factors; D055815:Young Adult
chemical_list: D001786:Blood Glucose