title: Conditions associated with very low values of glycohaemoglobin measured by an HPLC method.
abstract: OBJECTIVE
  To identify the causes of very low glycohaemoglobin (GHb) values in a sample of patients with diabetes in southern Brazil using high performance liquid chromatography.
  
  
  METHODS
  Between August 1996 and December 2001 all samples from patients with diabetes at a university hospital with GHb values below the reference range (4.7-6.0% HbA(1c)) were submitted to cellulose acetate electrophoresis. Medical records were reviewed to identify conditions that might be associated with these low values.
  
  
  RESULTS
  Among 29 657 samples analysed, 130 patients had GHb < 4.7%. Seventy three patients (56%) were heterozygous for HbS, HbC, or HbD (19 black, two mulatto, and 52 white patients). The other 57 patients (44%) without Hb variants had low haematocrit and haemoglobin values (42 patients) or other conditions such as pregnancy, lipaemia, malignancy, cirrhosis, acetylsalicylic acid use, and absence of diabetes (15 patients).
  
  
  CONCLUSIONS
  The presence of an Hb variant may falsely lower GHb measurements. However, anaemia is also a source of negative interference. The haematological status should be considered for the correct interpretation of GHb results.
authors.affiliation: Clinical Pathology Department, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil. jcamargo@hcpa.ufrgs.br
authors.forename: J L
authors.initials: JL
authors.lastname: Camargo
authors.forename: J L
authors.initials: JL
authors.lastname: Gross
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000740:Anemia / Q000097:blood; D001938:Brazil; D002648:Child; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D003920:Diabetes Mellitus / Q000097:blood*; D005260:Female; D006442:Glycated Hemoglobin / Q000032:analysis*; D006400:Hematocrit; D006441:Hemoglobin A / Q000032:analysis; D006801:Humans; D008297:Male; D008875:Middle Aged; D012680:Sensitivity and Specificity; D018709:Statistics, Nonparametric
chemical_list: D006442:Glycated Hemoglobin; D006441:Hemoglobin A