In clinical practice, glycemic control is generally assessed by measuring and interpreting glycated hemoglobin levels, however, this test should be run under standardized conditions. We focus here on the crucial steps to ensure IFCC standardized HbA1c results, pointing out several residual weak points, mostly relating to the laboratory end-user (calibration, quality control materials, and EQAS). We also review the use of HbA1c for diagnosing diabetes and the various indicators useful for assessing glucose variability because in some cases they seem to represent a patient's glucose profile more accurately than one-off HbA1c assays. Finally, the potential utility of glycated albumin and the glycation gap, the costs involved and the laboratory management issues are briefly discussed.