Estimated Average glucose
(eAG) correlates directly to HbA1C.
AACC advises labs to report
eAG.
That term, “estimated average glucose (eAG),” refers to the
result of a diabetic’s
glycated hemoglobin (A1c)
test, converted into an average blood glucose level in the
units of measure seen on glucose meters. Both the American
Diabetes Association (ADA) and the American Association for
Clinical Chemistry (AACC) hope that using eAG helps patients
and their doctors make the necessary changes to diet and
physical activity to improve overall
diabetes
management.
Part of the logic for choosing the term “eAG” is
that the medical community recently adopted another new term,
eGFR, for estimated glomerular filtration rate, which was
introduced as an easier to understand measure of kidney
function than the established method of measuring creatinine
levels to assess kidney function. The hope is that the growing
acceptance of eGFR will help spur the adoption of the similar
eAG.
The American Diabetes Association (ADA),
European Association for the Study of Diabetes (EASD), and
International Diabetes Federation (IDF) will be working
together to conduct educational efforts to make both patients
and providers aware of this new terminology, and help to
understand the relationship between A1C and
eAG.
A mathematical relationship between the average glucose level
over the preceding three months and levels of the A1C test,
thus yielding translation of the A1C for reporting as estimated
average glucose (eAG), was proven in an international study
published online today in the August issue of Diabetes
Care.
There are
two formulae for deriving eAG from percentage HbA1c. Using
metric units, eAG (mg/dL)=28.7XHbA1c-46.7. Using SI
units, eAG (mmol/L)=1.59XHbA1c-2.59
A group of international investigators conducted a 10-center
study to try to define, as accurately as possible, the
relationship between average blood glucose levels and A1C. The
study recruited 507 volunteers of various races and
ethnicities: 268 type 1, 152 type 2, and 80 without diabetes.
The study measured A1Cs in a central laboratory monthly for 3
months, and measured average glucose levels using a combination
of continuous glucose monitoring and frequent self-monitoring
of blood glucose levels.
Comparison of A1C and eAG
levels
|
A1C %
|
eAG (mg/dl)
|
eAG (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
|
TO CONVERT YOUR A1C VALUE To
eAG
http://professional.diabetes.org/GlucoseCalculator.aspx
-American Diabetes Association-
|