STANDARDIZATION OF HBALC VALUE AND ITS COMPARISON TO IMMUNOASSAY - 2 YEARS OF EXPERIENCE

In spite of the routine use of hemoglobin Ale (HbAlc) value to guide d iabetes therapy, substantial differences have been noted between resul ts obtained by different instruments and laboratories. It was suggeste d that confusion between the terms used for HbAlc, i.e. between 'total HbAlc', which includes labile content, and 'stable HbAlc', which does not, may account for some of these inter-instrument and inter-laborat ory differences. However, an undesirable difference was found even in measurements of only the stable component of HbAlc using the two most commonly used HPLC analyzers in our country. We found that a two-point calibration using lyophilized hemoglobin at lower and higher ranges w as effective in matching up results of HbAlc measurement. This finding was concordant with a report by the Committee of the Japan Diabetes S ociety and other reports. Two methods of HbAlc immunoassay, one perfor med with the DCA 2000 automated analyzer and another performed using t he Liquitech kit or a general automated analyzer, were evaluated and f ound to perform as well as HPLC analyzers in all respects except preci sion. The results derived from immunoassay were in good agreement with the calibrated results by HPLC, with (Liquitech) and without (DCA 200 0) conversions.