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.
GMI Calculation: How is Glucose Management Indicator Calculated?
In order to determine a GMI calculation, it is necessary to compute the average glucose level and transform it from milligrams per deciliter (mg/dL) to a percentage.
The formula for calculating the GMI as a percentage is: GMI (Percentage) = 3.31 + 0.02392 x (glucose reading in mg/dL).