(A) Even in patients with the same glycosylated hemoglobin (HbA1c) or mean glucose, exact glycemic control may vary. For example, some patients can have excellent glycemic control, spending the whole day with glucose levels between 70 and 180 mg/dL; on the other hand, some patients’ glucose levels may range from 50 to 250 mg/dL. (B) Self-monitoring blood glucose (SMBG) cannot fully capture actual glycemic fluctuation like continuous glucose monitoring (CGM) measuring interstitial glucose level every 5 to 15 minutes (96 to 288 measurements/day). TAR, time above range; TBR, time below range; TIR, time in range.