HbA1c test (hemoglobin A1c test, glycosylated hemoglobin A1c test,
glycohemoglobin A1c test, or A1c test) is a lab
test which reveals average blood glucose over a period of two to three
months. Specifically, it measures the
number of glucose molecules attached to hemoglobin, a substance in red blood
test takes advantage of the lifecycle of red blood cells. Although constantly
replaced, individual cells live for about four months. So by measuring attached glucose in a current blood sample, average blood sugar
levels over the previous two to three months can be determined.
test results are expressed as a percentage, with 4 to 6 % considered normal.
The HbA1c "big picture" complements the day to day "snapshots" obtained from the
self-monitoring of blood glucose (mg/dl), and the two tests can be equated as in the
interpreting your hemoglobin test you should keep in mind that results differ
depending on the test method used. Some labs measure hemoglobin A1 (which
is different than hemoglobin A1c). Also,
realize that HbA1c results may reflect the averaging of a period of high
glucose with a period of low glucose, as opposed to the consistent readings required
for good control. To
best understand your HbA1c results always consult your healthcare professional.
To view a list of popular
diabetes guide books with more information about the HbA1c test, blood glucose and related
If you are interested in a
simple means of tracking your ongoing HbA1c
range you can download the Diabetes Chart HbA1c
Diabetes Association. American Diabetes Association Complete Guide to
Diabetes. Alexandria, VA: American Diabetes Association, 2005.
Richard S., M.D., and Amy P. Campbell.
The Joslin Guide to Diabetes: A Program
for Managing Your Treatment.
New York: Fireside Books, 2005.
• Zerhouni, Elias A., "Report
on Closing the Disparity Between Hemoglobin A1c Treatment Guidelines and
Practice," US Department of
Health and Human Services, National Institutes of Health, National Institute of
Diabetes and Digestive and Kidney Diseases, 2007: 6-7.
Page created September 14, 2000 and last updated August 3, 2011