Variabilità biologica dell’emoglobina glicata: un’analisi sistematica della letteratura

Glycated hemoglobin (HbA1c) is the product of the nonenzymatic reaction between glucose and the free amino group of the valine of hemoglobin A0 β-chain. HbA1c is the most important marker for monitoring of the glycemic state in diabetic patients. Different analytical techniques are available for HbA1c determination. The lack of comparability between data from different methods resulted in the need to develop a uniform, scientifically sound, international reference system for HbA1c, i.e. the IFCC reference system. Today, the standardisation of the HbA1c measurement is finally in place, but a clear definition of the clinically allowable total error of measurements is still lacking. Information from biological variation of the analyte can be used to derive these goals. In this study, we systematically reviewed the published studies defining the biological variation of HbA1c to check consistency of available data in order to accurately define analytical goals. All the eight recruited studies showed limitations on the employed analytical methodology, on selected population, and in applying the correct protocol and statistical analyses. In conclusion, there is an urgent need of an accurately designed study to determine biological variability of HbA1c using a traceable and specific assay, appropriate protocol and right statistical derivation of data.