Improvement in the Quality of HbA1c Determination by Using Commutable Specimens With IFCC-Assigned Values

Abstract

Background: To assess the usefulness of commutable secondary reference materials with International Federation of Clinical Chemistry (IFCC)-assigned values, for improving the quality of hemoglobin A1c (HbA 1c ) determination.

Methods: We recalibrated and evaluated 3 point-of-care-test (POCT) devices via 3 different method-specific central laboratory analyzers that were calibrated using commutable specimens with IFCC-assigned values. The staff members who performed POCT were also evaluated before and after training.

Results: HbA 1c levels measured with POCT devices showed significantly lesser bias after external mathematical calibration. The interlaboratory CVs for HbA 1c measurements decreased from 12% to 4% after training of POCT-device-operating personnel in the NycoCard group. The CVs in the DCA Vantage and Afinion groups also improved after training.

Conclusion: Calibration of laboratory devices by specimens with IFCC-assigned values and by external mathematical calibration could improve the accuracy of POCT HbA 1c measurements. Also, standardized training could improve precision in POCT HbA 1c measurements, especially for semiautomated HbA 1c POCT devices.

Keywords: hemoglobin A1c; laboratory analyzers; point-of-care testing devices; standardization.