Mean Glucose
Definition
The arithmetic average of all glucose readings over a specified period, calculated from the 288 or more daily readings that most CGMs capture (one reading every 5 minutes). Mean glucose is a core input for calculating the Glucose Management Indicator (GMI) and correlates with A1C, though the relationship is not perfectly linear for all individuals. A mean glucose of 154 mg/dL corresponds to an estimated A1C of approximately 7.0%, and each 25 mg/dL increase in mean glucose raises estimated A1C by roughly 0.5%.
Why “Mean Glucose” Matters for Glucose Monitoring
Understanding mean glucose is essential for anyone using or evaluating a continuous glucose monitor. This concept directly affects how CGM devices are designed, how glucose data is interpreted, and how clinical decisions about blood sugar management are made. CGM metrics transform thousands of raw glucose readings into actionable numbers that clinicians use to assess glucose control, adjust medications, and set treatment goals.
This term applies broadly across all continuous glucose monitors and is foundational knowledge for interpreting CGM data, whether you are managing diabetes or using a sensor for metabolic wellness.
Related Terms
An estimated A1C value calculated from CGM mean glucose data, allowing users to track their A1C-equivalent in real time without requiring a laboratory blood draw.
Hemoglobin A1C is a blood test that measures the percentage of hemoglobin proteins coated with sugar, reflecting average blood glucose levels over the previous 2 to 3 months.
A statistical measure of how widely glucose values are spread around the mean glucose over a given period.
A standardized one-page glucose report recommended by the International Diabetes Center that summarizes 14 days of CGM data into a visual profile showing median glucose, interquartile range (25th to 75th percentile), and 10th to 90th percentile bands across a 24-hour period.