Comparison of Two Ion-Exchange HPLC Methods for HbA1c Quantitation

Area of Science:

• Clinical Chemistry
• Analytical Biochemistry
• Diabetes Diagnostics

Background:

• Evaluation of the newest-generation Tosoh Automated Glycohemoglobin Analyzer HLC-723GR01 (GR01).
• Comparison against the predicate Tosoh HLC-723G8 glycohemoglobin analyzer (G8).

Purpose of the Study:

• To characterize the analytical performance of the GR01 analyzer.
• To assess precision, linearity, method comparison, and variant interference.
• To validate the GR01 against the established G8 method.

Main Methods:

• Performance assessment in whole blood and hemolysate.
• Precision, linearity, and method comparison studies using the G8 as the comparator.
• Variant interference studies with hemoglobin C, D, E, S, A2, and F.

Main Results:

• GR01 exhibited total imprecision of approximately 1% CV for HbA1c levels from 5.0% to 12.0%.
• Linearity studies met acceptance criteria with minimal bias (average 0.1%).
• Method comparison showed relative differences <5% in nonvariant specimens and mean differences of 0.1% (SD 0.25%) across all variants.

Conclusions:

• The GR01 demonstrates excellent correlation with the G8, including specimens with high hemoglobin variant concentrations.
• Relative bias near medical decision points (6.5% and 8.0%) met the National Glycohemoglobin Standardization Program's ±5% criterion.
• The GR01 is a reliable analyzer for accurate HbA1c measurement.