Glucose Management Indicator (GMI) approximates the laboratory A1C level expected based on average glucose measured using continuous glucose monitoring (CGM) values. Average glucose is derived from at least 12 days of CGM data. The GMI may be similar to, higher than, or lower than the laboratory A1C. Differences between GMI and laboratory A1C may reflect differences among an individual’s red blood cell lifespan, how glucose binds to hemoglobin, or due to a recent fluctuation in glucose control.