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[An interlaboratory standardization of HbA1c determination in Japan]
1Department of Laboratory Medicine, School of Medicine, University of Tokushima.
Insights
Interlaboratory differences in Hemoglobin A1c (HbA1c) measurements were significantly reduced by standardizing procedures to measure only the stable component. This standardization improved accuracy and established new reference intervals for healthy individuals.
Area of Science:
- Clinical Chemistry
- Laboratory Medicine
- Analytical Chemistry
Background:
- Significant interlaboratory variability exists in Hemoglobin A1c (HbA1c) measurements.
- A high coefficient of variation (CV) of 10.5% was observed among 107 Japanese laboratories for fresh blood samples.
- Variations are attributed to differing evaluations of labile HbA1c components and instrument-specific measurements.
Purpose of the Study:
- To investigate and reduce interlaboratory differences in HbA1c measurements.
- To identify the primary sources of variation in HbA1c testing.
- To establish standardized reference intervals for HbA1c.
Main Methods:
- Laboratories were instructed to measure only the stable HbA1c component.
- Common calibration standards were utilized across participating laboratories.
- HbA1c levels were measured in 725 healthy subjects using the standardized procedure.
Main Results:
- Interlaboratory differences in HbA1c values were markedly reduced.
- The coefficient of variation (CV) decreased significantly to 2.82% after standardization.
- Reference intervals for HbA1c in healthy subjects were determined to be 4.3% to 5.8%.
Conclusions:
- Standardizing HbA1c measurement to focus on the stable component effectively minimizes interlaboratory variation.
- The developed standardized procedure provides a more reliable method for HbA1c testing.
- The established reference intervals offer a benchmark for clinical interpretation of HbA1c results.
Abstract:
A survey of the actual state of interlaboratory differences in HbA1c values revealed a great variation of the values among 107 laboratories throughout Japan; the coefficient of variation (CV) for measurements of fresh blood samples was as high as 10.5%. On the basis of this results, it became apparent that this large interlaboratory variation was mainly due to differences in evaluation of a labile HbA1c component and in values measured with an instrument of one manufacture with another. To verify this assumption, we asked the laboratories to measure only a stable component using common calibrations. These procedures resulted in a marked reduction of the interlaboratory difference in HbA1c values; the CV decreased to 2.82%. The reference intervals of HbA1c calculated from the HbA1c results of 725 healthy subjects measured using the standardized procedure was from 4.3% to 5.8%.