Www.egms.de/static/p Df/journals/gms/2011 -9/000151.pdf

Glycated haemoglobin (HbA1c) measurements are used in clinical studies and for the management of diabetic patients. Various efforts were made to standardize the HbA1c measurements with consensus standards and standards based on a reference measurement procedure with external calibration. According to ISO 17511, a standard should meet the highest accuracy possible, have a defined uncertainty of measurement, and the calibration should be traceable to SI units. For HbA1c, this has been realized using a LC-ID-MS procedure based on the existing reference measurement procedure. The International Federation of Clinical Chemistry (IFCC) established a Working Group to develop an international reference measurement procedure for HbA1c traceable to a standard of higher metrological order. The IFCC reference measurement procedure was developed using chromatographically purified HbA0 and HbA1c preparations from human blood as calibrators. The results between laboratories were regularly monitored by intercomparison surveys, and the quality of measurements was improved during the measurement campaigns. Since 2007, laboratories in Europe, Australia, and Japan calibrated their analytical systems for HbA1c according to the IFCC reference measurement procedure and started to report their results in mmol/mol. A recent study achieved the traceability of HbA1c measurement results to SI units by isotope-dilution mass spectrometry using glycated and non-glycated β-N-terminal hexapeptides of defined purity and stated uncertainty of measurement as calibrators.