title: Continuous glucose monitoring system: dawn period calibration does not change accuracy of the method.
abstract: BACKGROUND
  Continuous glucose monitoring system is a valuable instrument to measure glycemic control, which uses a retrospective calibration based upon 3 to 4 capillary glucose meter values inserted by the patient each day.
  
  
  OBJECTIVE
  We evaluated the interference of calibration during the dawn period in the system accuracy.
  
  
  METHODS
  The monitoring data were retrospectively divided into two groups: with (Group A) or without (Group B) the dawn period calibration (between 1:00 and 5:00 AM). Accuracy of the method was expressed by relative absolute difference.
  
  
  RESULTS
  Thirty-four continuous glucose monitoring data were evaluated comprising a total of 112 nights. A total of 289 paired readings were analyzed - 195 in Group A and 94 in Group B. We did not find a difference in relative absolute difference (RAD%) in any analyzed period of day by adding dawn calibration.
  
  
  CONCLUSIONS
  These data suggest that dawn calibration does not alter accuracy of method.
authors: Unidade de Diabetes, Divisão de Endocrinologia e Metabologia, Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brazil. guakau@yahoo.com.br
authors: Gustavo A
authors: GA
authors: Augusto
authors: André G P
authors: AG
authors: Sousa
authors: Marcela N A
authors: MN
authors: Perazo
authors: Maria L C
authors: ML
authors: Correa-Giannella
authors: Marcia
authors: M
authors: Nery
authors: Karla F S de
authors: KF
authors: Melo
mesh_terms: D000293:Adolescent; D000328:Adult; D001786:Blood Glucose / Q000378:metabolism*; D015190:Blood Glucose Self-Monitoring / Q000379:methods* / Q000592:standards; D002138:Calibration; D002940:Circadian Rhythm; D003920:Diabetes Mellitus / Q000097:blood*; D004812:Epidemiologic Methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D013997:Time Factors; D055815:Young Adult
chemical_list: D001786:Blood Glucose