Monitoring HbA1c requires methods with very tight CV’s. and BioRad cation exchange HPLC was the only method that detected and reported the presence of variant haemoglobins.  Recently SEBIA launched a capillary electrophoresis method for HbA1c, where an increase in resolution time for each sample was compensated for by 8 capillaries running in parallel to achieve a similar output per hour to the Variant II. In this study we have compared the SEBIA Capillarys and the BioRad Variant II Nu.

            Over 120 samples the concordance correlation coefficient was 0.996,  Pearson Precision Coefficient of 0.997 and a bias correction factor of 0.999, demonstrating the strong agreement between the two methods. Individual capillaries had CV’s between 0.69 and1.7% (N=16) at the critical cut off point of 6% HbA1c. Inter assay variation CV was between 0.45 to 1.34% (N-16) and Intra assay variation CV was between 0.86 to 1.6% (N=16).

Interassay variation

HbA1c was linear from 0.9 to 12.6% and was unaffected by 5 fold dilution of the original sample haemoglobin (Hb). Labile HbA1c , carbamalyted HbA1c or high bilirubin up to 199 mmol/L did not interfere with HbA1c. The results clearly identified the major Hb variants and most of the glycated Hb variants because of the clear separation of peaks and the analysis software flagged abnormal HbA1c profiles.  The instrument operation is intuitive, has easy to use software to and has both NGSP and IFCC certification and produces results in both units.

We thank Diagnostic Solutions for providing the instrument and the reagents.