Glycated haemoglobin analyses--assessment of within- and between-laboratory performance in a large UK region.

The performance of glycated haemoglobin methods has been assessed in 20 laboratories. The methods used in these laboratories were affinity chromatography, electroendosmosis and ion-exchange chromatography. Assessment was based on the results returned by the participating laboratories on distributed specimens. Each method displayed acceptable precision and good linearity. Overall there were substantial differences in results reported by different laboratories, though within each method group these differences were less marked.