The A1C test is subject to certain limitations.
Conditions that affect red blood cell
turnover (hemolysis, blood loss) and hemoglobin
variants must be considered,
particularly when the A1C result does
not correlate with the patient’s blood glucose
levels (3). For patients in whom A1C/
estimated average glucose (eAG) and
measured blood glucose appear discrepant,
clinicians should consider the possibilities
of hemoglobinopathy or altered
red blood cell turnover and the options
of more frequent and/or different timing
of SMBG or CGM use. Other measures of
chronic glycemia such as fructosamine
are available, but their linkage to average
glucose and their prognostic significance
are not as clear as for A1C.