Hemoglobin A1c: past, present and future.

Area of Science:

• Clinical Chemistry
• Endocrinology
• Diabetes Mellitus Research

Background:

• Hemoglobin A1c (HbA1c) is a long-established marker for monitoring glycemic control in diabetes.
• Current diabetes screening and diagnosis primarily rely on plasma glucose measurements, which have limitations.

Purpose of the Study:

• To review recent advancements in HbA1c testing and its potential diagnostic applications.
• To evaluate the evolving role of HbA1c in diabetes screening and diagnosis.

Main Methods:

• Review of recent literature on HbA1c methodologies and diagnostic capabilities.
• Analysis of proposed changes for HbA1c standardization, including revised reference ranges and units.
• Comparison of HbA1c's diagnostic potential against current plasma glucose-based guidelines.

Main Results:

• Standardization efforts suggest lower HbA1c reference ranges and revised units (e.g., %, mg/dL, mmol/mol).
• Existing plasma glucose diagnostic methods have shortcomings, highlighting a need for alternative approaches.
• Emerging evidence supports HbA1c's diagnostic accuracy.

Conclusions:

• Despite ongoing reassessment and developments, HbA1c is not currently recommended for diabetes diagnosis.
• Future practice guidelines may consider a diagnostic role for HbA1c, supported by recent literature and expert recommendations.
• The US Endocrine Society recently proposed initial recommendations for HbA1c's diagnostic use.