Standardization of HbA1c: good or bad?

Area of Science:

• Clinical Chemistry
• Laboratory Medicine
• Diabetes Diagnostics

Background:

• The International Federation for Clinical Chemistry (IFCC) has developed a reference measurement system for HbA1c.
• This system enables standardized reporting of true HbA1c values globally.
• Previous harmonization assays, like the Diabetes Control and Complications Trial (DCCT), used different units.

Purpose of the Study:

• To introduce the IFCC reference measurement system for HbA1c.
• To evaluate the relationship between the IFCC assay and existing harmonization assays.
• To highlight the implications of the new standardized reporting for clinical practice and patient care.

Main Methods:

• Development of a true reference measurement system for HbA1c by the IFCC.
• Establishment of regression equations between the IFCC assay and harmonization assays (including DCCT).
• Analysis of the linearity, tightness, and stability of these regression equations over time.

Main Results:

• The IFCC reference system allows for true, standardized HbA1c reporting worldwide.
• Regression equations between IFCC and DCCT assays are linear, tight, and stable.
• The new IFCC units (mmol/mol) differ significantly from DCCT units (percentage).

Conclusions:

• The IFCC system facilitates easier target setting, auditing, and translation of research into practice.
• A significant disadvantage is the difference in units, necessitating extensive education for patients and professionals.
• The IFCC system does not resolve inherent measurement and interpretation challenges of HbA1c, such as with red blood cell disorders.