title: Evaluation of conditions associated with glycated hemoglobin values below the reference range.
abstract: BACKGROUND
  Evaluation of conditions associated with glycated hemoglobin (HbA1c) values below the reference range in HbA1c determinations.
  
  
  METHODS
  Over a time period of 5 years, HbA1c results were determined with the ion-exchange high-performance liquid chromatography (HPLC) method HA-8140 Menarini.
  
  
  RESULTS
  Of approximately 20 000 HbA1c results analyzed, 9 were below the reference range. The reason for HbA1c values below the reference range was found to be liver cirrhosis in 6 patients, anemia with hematological neoplasms in 2 patients, and elevated fetal hemoglobin > 1.5% in one patient. The silent hemoglobin (Hb) variant Hb Graz in 6 patients, Hb Sherwood Forest in 1 patient, homozygote HbS in one patient, and gross hypertriglyceridemia in one patient demonstrated no HbA1c result.
  
  
  CONCLUSIONS
  In patients with liver cirrhosis, HbA1c measurements should be used with caution when evaluating long-term glucose control, and samples with suspected Hb variants should be analyzed by hemoglobin electrophoresis. Our study underscores the need for clinical laboratories and physicians to be aware of the limitations of their HbA1c assay methods as well as of the importance of visual inspection of ion-exchange chromatograms to detect HbA1c values below the reference range and abnormalities caused by the interference factors described here.
authors: Dept. of Internal Medicine, Medical University of Graz, Graz, Austria. w.schnedl@dr-schnedl.at
authors: Wolfgang J
authors: WJ
authors: Schnedl
authors: Theresa
authors: T
authors: Lahousen
authors: Robert
authors: R
authors: Krause
authors: Sandra J
authors: SJ
authors: Wallner
authors: Claudia
authors: C
authors: Piswanger-Soelkner
authors: Rainer W
authors: RW
authors: Lipp
mesh_terms: D000740:Anemia / Q000097:blood* / Q000150:complications; D002851:Chromatography, High Pressure Liquid / Q000379:methods / Q000592:standards; D002852:Chromatography, Ion Exchange / Q000379:methods / Q000592:standards; D005319:Fetal Hemoglobin / Q000032:analysis*; D006442:Glycated Hemoglobin / Q000032:analysis*; D019337:Hematologic Neoplasms / Q000150:complications* / Q000473:pathology; D006455:Hemoglobins, Abnormal / Q000032:analysis; D006801:Humans; D008103:Liver Cirrhosis / Q000097:blood* / Q000473:pathology; D012016:Reference Values; D012189:Retrospective Studies
chemical_list: D005319:Fetal Hemoglobin; D006442:Glycated Hemoglobin; D006455:Hemoglobins, Abnormal