The American Diabetes
Association now recommends measurement of HbA1c as the most appropriate
test to use for the diagnosis of diabetes. Details can be found in the
January issue of
Diabetes Care. This recommendation makes perfect sense for
several reasons, not the least of which is that the patient does not need to be
fasting for the test so it can be done in your office at the time of the
patient visit there are several point of care (POC) systems available
Not so fast!
The current issue of the journal Clinical Chemistry, the
journal of the American Association for
Clinical Chemistry, has an article and an editorial pointing out that only
two of the available POC systems for HbA1C measurement are reliable. The
variability issues with the POC systems also affect serial monitoring which is
clinically as important as initial screening.
Not what you wanted to hear! I must quickly add that the available
laboratory methods for HbA1c are all felt to be reliable, so if you are not
measuring HbA1c in your office follow the recommendation of the ADA: The
test should be performed in a laboratory using a method that is National
Glycohemoglobin Standardization Program (NGSP) certified and standardized to
the Diabetes Control and Complications Trial (DCCT) assay.
If you do measure HbA1c in your office, please read the Clinical
Chemistry articles and make changes as appropriate.
An HbA1c level >6.5% is diagnostic but is not necessarily an
indication to begin pharmacologic therapy. That decision will depend on many
other factors including personal medical history, family history, BMI, blood
pressure, fasting glucose and lipid profile. A fasting glucose <126 mg/dL in
the presence of an elevated HbA1c in a previously undiagnosed patient should
not negate the diagnosis of diabetes but should point you and the patient in
the direction of lifestyle modification as the first line of intervention. This
is of course essential for all patients with type 2 diabetes no matter how far
from 'normal' the lab results are.
The number and classes of drug therapies for type 2 diabetes has
expanded substantially over the last decade and continues to grow. The number
of persons newly diagnosed with diabetes appears to be expanding even faster,
with the most rapid expansion being in waist circumference. The only thing
'wearing thin' is the number of excuses we hear for not being able to lose
weight to help control or stave off diabetes and other preventable conditions.
Many are unfortunately legitimate many more are just excuses!