Before 1980, we measured blood sugar levels by how much sugar was present in our urine. If the test showed a negative result for our urine sugar, all that meant was our actual blood sugar was under 200 mg/dl. At the time, that was the best way to measure our diabetes control.
The 1980s brought a new standard of care, introducing the A1C and the glucometer. What does the A1C tell us? If you have an A1C of 7.0, that means you’ve had an average blood sugar of 150 mg/dl for the prior 90 days. It was considered state-of-the-art. But … does this method of testing really show us how well we’re controlling our diabetes?
Your blood sugar for the first 45 of that 90 days could be running constantly at 100 mg/dl. Then, during the second 45 days, your blood sugar could be running steady at 300 mg/dl. These disparate levels combine to result in an A1C of 7.0. Let’s say, for another example, that your blood sugar level was alternating, daily, between 100 mg/dl and 300 mg/dl. Every other day, your blood sugar rose to 300. After 90 days, your resulting A1C would be 7.0. While the A1C is an important test, it does not accurately report our level of control.