A1c and average glucose level

A1c and average glucose level

The results of the A1C-Derived Average Glucose study (ADAG), published in Diabetes Care this month, have affirmed the existence of a linear relationship between A1C and average blood glucose levels. Prior studies using limited numbers of meter glucose readings primarily in type 1 Caucasian populations had been used in the past to estimate average glucose. The international ADAG study clarified the very close linkage using about 2700 glucose readings per subject per A1C measurement, and verified that the relationship holds in people with type 1 and type 2 diabetes, of all ages, of both genders, and across ethnic/racial groups. The “new numbers” are somewhat different than those in the old tables of A1C vs. average glucose.

In light of the study results, health care providers can confidently report A1C results to patients using the same units (mg/dl or mmol/l) that patients see routinely in blood glucose measurements. For more information about the ADAG study, a table of A1C and the corresponding estimated average glucose, an eAG calculator, and other materials, go to http://professional.diabetes.org/glucosecalculator.aspx

The relationship between A1C and eAG is described by the formula 28.7 * A1C – 46.7 = eAG.
        A1C     eAG                    
        %       mg/dl   mmol/l         
        6       126     7.0            
        6.5     140     7.8            
        7       154     8.6            
        7.5     169     9.4            
        8       183     10.1           
        8.5     197     10.9           
        9       212     11.8           
        9.5     226     12.6           
        10      240     13.4