Table 6.1 shows the correlation between
A1C levels and mean glucose levels based
on two studies: the international A1CDerived
Average Glucose (ADAG) trial,
which based the correlation with A1C
on frequent SMBG and CGM in 507 adults
(83% non-Hispanic whites) with type 1,
type 2, and no diabetes (25), and an empirical
study of the average blood glucose
levels at premeal, postmeal, and bedtime
associated with specified A1C levels using
data from the ADAG trial (21). The American
Diabetes Association (ADA) and the
American Association for Clinical Chemistry
have determined that the correlation
(r 5 0.92) in the ADAG trial is strong
enough to justify reporting both the A1C
result and the eAG result when a clinician
orders the A1C test. Clinicians should
note that the mean plasma glucose numbers
in the table are based on ;2,800
readings per A1C in the ADAG trial.