Abstract
Background:
Glycated hemoglobin, reported as hemoglobin A1c (HbA1c), is widely used as a measure of long-term glycemic control in patients with diabetes. The accuracy of measurements depends in part on proper storage of the sample prior to analysis.
Methods:
Three whole blood (WB) samples at three HbA1c levels were collected and stored at −70°C, −20°C, 4°C, room temperature (17–23°C), and 37°C. One aliquot from each temperature was analyzed by each method on days 1, 2, 3, 6, 7, 10, 14, 21, 28, and 57.
Results:
The Primus CLC (385 and 330) (Primus Corp., Kansas City, MO) showed stability of WB at −20°C and 4°C for 57 days, room temperature for 14 days, and 37°C for 1 day. The Tosoh 2.2 Plus (Tosoh Bioscience, Inc., South San Francisco, CA) showed stability at −20°C for 3 days, 4°C for 14 days, room temperature for 3 days, and 37°C for less than 24 h. With the Tosoh G7, results were acceptable at −20°C for 10 days, 4°C for 57 days, room temperature for 7 days, and 37°C for less than 24 h. The Bio-Rad Variant (Bio-Rad Laboratories, Hercules, CA) showed stability at −20°C for 6 days, 4°C for 14 days, room temperature for 3 days, and 37°C for less than 24 h. The Bio-Rad Variant II showed stability at −20°C for 28 days, 4°C for 57 days, room temperature for 7 days, and 37°C for less than 24 h.
Conclusions:
All methods either met or exceeded manufacturers′ claims for stability. The CLC 385/330, Tosoh G7, and Bio-Rad Variant II high performance liquid chromatography methods showed better stability than the Tosoh 2.2 Plus and Bio-Rad Variant.
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