Interpretation of HbA1c lies at the intersection of analytical methodology, clinical biochemistry and hematology (Review)

Over past few decades, diabetes has become widespread on a global scale. Hemoglobin A1c (HbA1c) assessment is crucial for diabetes care, since it allows for the monitoring of an individual's level of glycemic control over the course of 2 to 3 months and risk assessment to determine any possible complications. Numerous methods, including cation-exchange chromatography, electrophoresis, immunoassays and affinity chromatography, can be used to determine the HbA1c level. Each method has its limitations, however. The amount of HbA1c in patient samples is not only dependent on blood glucose levels, but is also strongly influenced by changes in red blood cell lifespan and globin chain structure. Consequently, hematological, clinical biochemistry and analytical methods all intertwine when interpreting HbA1c. There are numerous reports on the interactions of HbA1c with inherited and acquired diseases. Some of these impacts are inconsistent and difficult to explain. The present review article aimed to summarize and classify these effects and evaluate their clinical relevance. The findings discussed herein may serve as a reminder that clinical HbA1c values need to be analyzed with caution.