title: Approved IFCC reference method for the measurement of HbA1c in human blood.
abstract: HbA1C is the stable glucose adduct to the N-terminal group of the beta-chain of HbA0. The measurement of HbA1c in human blood is most important for the long-term control of the glycaemic state in diabetic patients. Because there was no internationally agreed reference method the IFCC Working Group on HbA1c Standardization developed a reference method which is here described. In a first step haemoglobin is cleaved into peptides by the enzyme endoproteinase Glu-C, and in a second step the glycated and non-glycated N-terminal hexapeptides of the beta-chain obtained are separated and quantified by HPLC and electrospray ionisation mass spectrometry or in a two-dimensional approach using HPLC and capillary electrophoresis with UV-detection. Both principles give identical results. HbA1c is measured as ratio between the glycated and non-glycated hexapeptides. Calibrators consisting of mixtures of highly purified HbA1c and HbA0 are used. The analytical performance of the reference method has been evaluated by an international network of reference laboratories comprising laboratories from Europe, Japan and the USA. The intercomparison studies of the network showed excellent results with intra-laboratory CVs of 0.5 to 2% and inter-laboratory CVs of 1.4 to 2.3%. Possible interferences have been carefully investigated. Due to the higher specificity of the reference method the results are lower than those generated with most of the present commercial methods which currently are calibrated with unspecific designated comparison methods. The new reference method has been approved by the member societies of the International Federation of Clinical Chemistry and Laboratory Medicine and will be the basis for the future uniform standardization of HbA1c routine assays worldwide.
authors.affiliation: Department of Clinical Chemistry, Malmö University Hospital, Lund University, Sweden. jan-olof.jeppsson@klkemi.mas.lu.se
authors.forename: Jan-Olof
authors.initials: JO
authors.lastname: Jeppsson
authors.forename: Uwe
authors.initials: U
authors.lastname: Kobold
authors.forename: John
authors.initials: J
authors.lastname: Barr
authors.forename: Andreas
authors.initials: A
authors.lastname: Finke
authors.forename: Wieland
authors.initials: W
authors.lastname: Hoelzel
authors.forename: Tadao
authors.initials: T
authors.lastname: Hoshino
authors.forename: Kor
authors.initials: K
authors.lastname: Miedema
authors.forename: Andrea
authors.initials: A
authors.lastname: Mosca
authors.forename: Pierluigi
authors.initials: P
authors.lastname: Mauri
authors.forename: Rita
authors.initials: R
authors.lastname: Paroni
authors.forename: Linda
authors.initials: L
authors.lastname: Thienpont
authors.forename: Masao
authors.initials: M
authors.lastname: Umemoto
authors.forename: Cas
authors.initials: C
authors.lastname: Weykamp
mesh_terms: D001774:Blood Chemical Analysis / Q000379:methods* / Q000592:standards*; D002021:Buffers; D002138:Calibration; D002851:Chromatography, High Pressure Liquid / Q000295:instrumentation; D019075:Electrophoresis, Capillary; D005060:Europe; D006442:Glycated Hemoglobin / Q000032:analysis*; D006031:Glycosylation; D006801:Humans; D007564:Japan; D012016:Reference Values; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D021241:Spectrometry, Mass, Electrospray Ionization; D014481:United States
chemical_list: D002021:Buffers; D006442:Glycated Hemoglobin