title: Improved colorimetric assay for glycosylated hemoglobin.
abstract: This colorimetric assay for glycosylated hemoglobin can be performed in 120 min with equipment available in most clinical laboratories. The glucose moiety of glycosylated hemoglobin is converted to 5-hydroxymethylfurfural by heating with oxalic acid for 60 min is an autoclave at 124 degrees C and 124 kPa (18 lb/in.2). The adduct formed by reacting 2-thiobarbituric acid with hydroxymethylfurfural is measured photometrically and results are expressed either as nanomoles of hydroxymethylfurfural or as fructose equivalents. Within-assay and between-assay coefficients of variation were less than 2% and less than 3%, respectively. Comparison of results for 50 patients' specimens as measured by the present assay and as analyzed for hemoglobin A1c by liquid chromatography showed excellent correlation (r = 0.98).
mesh_terms: D002851:Chromatography, High Pressure Liquid; D003124:Colorimetry / Q000379:methods; D003920:Diabetes Mellitus / Q000097:blood*; D005632:Fructose; D005662:Furaldehyde / Q000031:analogs & derivatives; D006027:Glycosides / Q000032:analysis*; D006441:Hemoglobin A / Q000031:analogs & derivatives* / Q000032:analysis; D006801:Humans; D007202:Indicators and Reagents; D012016:Reference Values
chemical_list: D006027:Glycosides; D007202:Indicators and Reagents; D005632:Fructose; C008046:5-hydroxymethylfurfural; D006441:Hemoglobin A; D005662:Furaldehyde