What Is A1c? - Topic Overview
A1c is a test that shows the average level
of blood sugar over the past 2 to 3 months. People with
diabetes need to have this test done regularly to see
whether their blood sugar levels have been staying within a target
range. This test is also used to diagnose diabetes.
Blood for an A1c test can be collected at home or
at your doctor's office. Home testing may not be an option for everyone. Check with your doctor.
- Home testing. Home test kits for A1c
are available. Using the kit, you can use a lancet (a small needle) to take a
blood sample from a finger. Then, put a few drops of blood on a sample card.
Place the card in an envelope and send it to a lab for testing. The lab sends
the results of the test to you or your doctor.
- Doctor's office.
Some doctors, particularly endocrinologists, have blood-analysis equipment in
their offices that can test hemoglobin A1c blood levels from a finger stick.
The doctor can then review the results during the
- Laboratory testing. The most accurate measurement of
A1c level is done in commercial laboratories. These labs may be run
by local hospitals or large health clinics, or they may be independently owned.
Lab personnel check their equipment often, calibrate their machines on a
regular schedule, and are monitored by federal and state regulatory
authorities. A doctor's office sends the blood sample to the lab. How long it
takes to get results depends on the lab. You can have the test results reported
to you or your doctor.
A1c test results show your average blood sugar
level over time. The result is reported as a percentage. Your goal is to keep
your hemoglobin A1c level as close to the normal level as possible. Studies
suggest that the lower the A1c level, the lower the incidence of
The American Diabetes Association (ADA) recommends keeping the hemoglobin A1c
less than 7%.
The result of
your A1c test can also be used to estimate your average blood sugar
level. This is called your estimated average glucose, or eAG. Your eAG and A1c
show the same thing in two different ways. They both help you know about your
average blood sugar over the past 2 to 3 months.
The table below
shows A1c with estimated average glucose.
A1c and estimated average glucose (eAG)1
|Hemoglobin A1c %|
Estimated average glucose (mg/dL)
A1c levels for children and teens are different. For
children younger than 6 years old, the ADA recommends an A1c level less than
8.5%. In children 6 to 12 years old, the recommended level is less than 8%. And
in teens, the recommended level is less than 7.5%.2
Results of A1c tests that are read at different labs
vary, but standardization among labs is improving.