CGMs offer a level of information about your glucose health that traditional blood glucose meters cannot. While glucose meters can provide your blood glucose level at any given moment when you test, CGMs offer ongoing data every few minutes, collected automatically.
Estimated A1C
Because a CGM collects data so frequently, it can predict A1C levels relatively accurately. A1C is a measurement that estimates average blood sugar levels over the past three months, and it’s often used to assess diabetes management success. Your healthcare team likely has given you an A1C range to shoot for, and CGMs can help you stay on top of that. Some models estimate A1C with a feature called a glucose management indicator (GMI).
These CGM estimates do not always precisely match the A1C results you get from a blood test, but they should give users a general idea of their overall management, especially when combined with time-in-range reports.
Time in Range
Time in range is widely considered a very reliable measure of glucose control and overall quality of life with diabetes, and this information can only be tracked with a CGM.
Time in range refers to the proportion of time spent in an approved blood sugar range, neither too low nor too high. The most common general range used by diabetes authorities, and the standard setting on CGMs, is 70 to 180 milligrams per deciliter (mg/dL).
When your blood sugar is above 70 mg/dL and below 180 mg/dL for most of the day, it suggests you aren’t experiencing frequent hypo- or hyperglycemia episodes.