The communication summarizes: a) Evidence based data on analytical and clinical aspects of HbA1c measurement b) Data on reference methods, primary and certified reference materials of HbA1c c) Data on the international measurement system for HbA1c (NGSP) d) Description of certification processes for routine measurement systems and for routine clinical laboratories e) Data on the activities of European reference laboratory for the HbA1c assessment. Routine methods of HbA1c measurement should have a repeatability Ł 3 %, reproducibility Ł 5% and systematic difference from 95% of the confidence interval of reference method Ł 1 %. These are the criteria for routine method selection and laboratory validation of commercial measurement systems in routine clinical laboratories.

        Key words: HbA1c, reference methods, reference materials, reference measurement system, certification of routine methods.