title: Lack of correlation between 1,5-anhydroglucitol assay and oral glucose tolerance test in patients with cystic fibrosis.
abstract: OBJECTIVE
  To determine whether the 1,5-anhydroglucitol (1,5-AG) assay, which reflects serum glucose levels during the preceding 2 weeks, could be used as an alternative to the current standard screening test for cystic fibrosis-related diabetes (CFRD)-the oral glucose tolerance test (OGTT).
  
  
  METHODS
  Serum 1,5-AG, hemoglobin A1c (A1C), fructosamine, and glucose at various time intervals during the OGTT were measured in 10 patients, 19 to 36 years old, with cystic fibrosis. Correlation coefficients were calculated to compare 1,5-AG with A1C, fructosamine, and serum glucose levels during the OGTT, and the mean 1,5-AG, A1C, and fructosamine for normal glucose tolerance, impaired glucose tolerance (IGT), and CFRD were compared statistically.
  
  
  RESULTS
  On the basis of the 120-minute OGTT, 1 of the 10 study subjects had CFRD and 4 had IGT. The mean 1,5-AG for patients with normal glucose tolerance was not significantly different from that for patients with IGT (P = .063). The 1,5-AG value was not significantly correlated with serum glucose during the OGTT, A1C, or fructosamine.
  
  
  CONCLUSIONS
  In this pilot study, we found no significant correlation between 1,5-AG and glucose values during the OGTT or between 1,5-AG and other glycemic markers. Hence, the utility of the 1,5-AG assay for screening for CFRD in the population of patients with cystic fibrosis may be limited.
authors.affiliation: Department of Endocrinology, Walter Reed Army Medical Center, Washington, District of Columbia 20307, USA. Kate.Kinnaird@us.army.mil
authors.forename: Kate E H
authors.initials: KE
authors.lastname: Kinnaird
authors.forename: Tom J
authors.initials: TJ
authors.lastname: Sauerwein
mesh_terms: D000328:Adult; D001786:Blood Glucose / Q000032:analysis; D003550:Cystic Fibrosis / Q000097:blood / Q000175:diagnosis* / Q000378:metabolism; D003847:Deoxyglucose / Q000032:analysis*; D005260:Female; D019270:Fructosamine / Q000032:analysis; D005951:Glucose Tolerance Test; D006442:Glycated Hemoglobin / Q000032:analysis; D006801:Humans; D008297:Male; D055815:Young Adult
chemical_list: D001786:Blood Glucose; D003847:Deoxyglucose; D019270:Fructosamine; D006442:Glycated Hemoglobin; C517652:hemoglobin A1c protein, human; C006584:1,5-anhydroglucitol