Summary:A comparison of methods, two based upon 5-hydroxymethylfurfural determination (colorimetric using a semi-automated procedure and HPLC) and ion exchange chfomatography (HbAj using BioRad method) was performed. The influence of variables on 5-hydroxymethylfurfural determination is reported. The dialysis Step appears to be essential for an accurate determination of 5-hydroxymethylfurfural released from glycated haemoglobin. The adjustment of haemoglobin concentration to an accurately known level is required for the colorimetric method, in order to achieve the same background colour absorbance. For the HPLC method this Step is not necessary äs 5-hydroxymethylfurfural liberation was proved to be stoichiometric. The Sep Pak C-18 cartridge purification appears to be an improvement for the accurate determination of 5-hydroxymethylfurfural using HPLC. When the three methods were compared the overlap between normals and diabetics was found to be less, using the 5-hydroxymethylfurfural HPLC method, suggesting that this procedure, although more time consuming, seems to be more useful in the management of diabetes mellitus. Glycosyliertes Hämoglobin:Methodenvergleich zwischen 5-Hydroxymethylfurfuralbestimmung (Kolorimetrie bzw. HPLC) und lonenaustauschchromatographie (HbA\)