Abstract: Objective To investigate the stability differences of glycosylated hemoglobin A_1c(HbA_1c) measurement by 3 detection systems under different storage conditions. Methods Three whole blood samples anti-coagulated by ethylene diamine tetraacetic acid-K₂(EDTA-K₂) at 3 HbA_1c levels were collected and stored at room temperature(20-25℃), 4℃,-30℃ and -70℃. One aliquot from each temperature was analyzed by each method on day 1, 3, 5, 7, 14, 21, 28, 35, 42, 56 and 84. The 3 detection systems were Bio-Rad variant Ⅱ Turbo HbA_1c analyzer (positive ion exchange high performance liquid chromatography, Bio-Rad variant Ⅱ Turbo), Primus Ultra² HbA_1c analyzer (affinity high performance liquid chromatography, Primus Ultra²) and Roche Modular PPI automatic biochemistry analyzer and its reagents (inhibition immunoturbidimetry, Roche Modular PPI). Results The results of samples stored at -70℃ were similar at different days. The coefficient of variation (CV) for Bio-Rad variant ⅡTurbo was 2.12%-2.80%. The CV for Primus Ultra² was 2.19%-2.71%. The CV for Roche Modular PPI was 2.28%-2.91%. The Bio-Rad variant Ⅱ Turbo showed having stabilities at room temperature for 7 d, 4 ℃ for 14 d and -30℃ for 35 d. The Primus Ultra² showed having stabilities at room temperature for 14 d, 4℃ for 56 d and -30℃ for 84 d. The Roche Modular PPI showed having stabilities at room temperature for 14 d, 4℃ for 84 d and -30℃ for 84 d. Conclusions The HbA_1c measurement is differently detected by different systems under different storage conditions.

Key words: Glycosylated hemoglobin A_1c, Time, Temperature