How to Convert A1C to Average Blood Sugar
The conversion from A1C to estimated Average Glucose (eAG) is based on the ADAG (A1C-Derived Average Glucose) study. This study provided a mathematical formula that relates A1C levels to the average glucose levels measured by continuous glucose monitors and finger-stick tests.
The ADAG Formula
The standard clinical formula used by the American Diabetes Association (ADA) is:
Source: Nathan DM, et al. Translating the A1C assay into estimated average glucose values. Diabetes Care. 2008.
Why Convert A1C to eAG?
Most patients are more familiar with the numbers they see on their daily glucose meters (mg/dL) than they are with A1C percentages. Converting your A1C helps you understand what your "big picture" lab result means in terms of your daily testing values.
Clinical Accuracy & Factors
While the formula is highly reliable, it is important to note that certain conditions like anemia, pregnancy, or hemoglobin variants can affect the accuracy of the A1C test itself, which in turn affects the eAG calculation.
