the three methods of assesing glycemic control , hba1c , smbg and cgms provide distinct information , yet complementary at the same time . hba1c does not equally reflect the glycemic values over the three months that forego its determination . hba1c assesses the average glycemic exposure in time without being able to differentiate between preprandial and postprandial glycemia , possible hypo and hyper glycemia . this method is able to identify both hypoglycemic and hyperglycemic episodes allowing immediate therapeutic decisions and therefore a glycemic balance closer to normal . introduction of cgms in the assessment of the glycemic status represents a great technological advance . this glucose monitoring method clears glycemic balance abnormalities in an otherwise impossible to obtain manner , evaluating both therapeutic efficiency and glycemic control . even if cgm systems are far from being implemented at a large scale in current practice , they are about to change the diabetes management by providing an optimal glycemic control .