Best use of the recommended IFCC reference method, material and values in HbA1C analyses

Area of Science:

• Clinical Chemistry
• Laboratory Medicine
• Diabetes Diagnostics

Background:

• Continuous improvement in Finnish HbA1C surveys over 10 years, reducing coefficient of variation.
• Most HbA1C methods trace to the Diabetes Control and Complication Trial (DCCT) method, a now-discontinued HPLC technique.
• The International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) developed new reference materials and a method for HbA1C determination.

Purpose of the Study:

• To evaluate the correlation between Labquality Ltd. HbA1C survey results and established reference methods.
• To compare DCCT-aligned values with the new IFCC reference method values.
• To propose a calibration strategy for current methods using IFCC standards.

Main Methods:

• Analysis of Finnish HbA1C survey data from Labquality Ltd. over the past decade.
• Correlation analysis of Labquality Ltd. mean HbA1C values with The European Reference Laboratory for Glycohemoglobin and the IFCC reference method.
• Comparison of IFCC reference values (2.85–3.81%) with current DCCT values (4.0–6.1%).

Main Results:

• Significant improvements in HbA1C measurement consistency observed in Finnish surveys.
• Labquality Ltd. mean HbA1C values showed a near-perfect correlation (r = 0.999) with both European and IFCC reference values.
• IFCC reference values are substantially lower than current DCCT values.

Conclusions:

• The IFCC reference method provides a reliable standard for HbA1C measurement.
• A significant discrepancy exists between IFCC and DCCT values, necessitating careful interpretation.
• Calibration of current methods using IFCC reference materials to DCCT levels is recommended for clinical adoption.