Hemoglobin Test (HbA1c)
The glycated hemoglobin
test (HbA1c, also called "hemoglobin A1c" or "glycohemoglobin"
and sometimes incorrectly referred to as "glycosylated
hemoglobin test") is an important blood test to determine how
well your diabetes is being controlled. The test provides an
average of your blood sugar measurements over the past six to 12
weeks and is used in conjunction with home blood sugar monitoring
to make adjustments in your diabetes medicines.
Hemoglobin is a substance
within red blood cells that carries oxygen throughout your body.
When the level of sugar (glucose) in your blood is too high, the
sugar binds with the hemoglobin. When this happens, your
hemoglobin is "glycated."
When your diabetes is not
controlled (meaning that your blood sugars are too high), sugar
builds up in your blood and your hemoglobin becomes glycated. If
your sugar levels have been high over recent weeks, your HbA1c
test will be higher. The HbA1c test offers a picture of what your
blood sugar control has been like over the course of the past
three months or so.
For people without
diabetes, the normal range for the HbA1c test is between 4%-6%.
The goal for people with diabetes is to have an HbA1c less than
People with diabetes who
are on insulin should have this test every three months. The test
should be performed no sooner than every six weeks. Those who have
their diabetes under good control may be able to wait longer
between the blood tests.
by the Department of Endocrinology and Department of Patient
Education and Health Information at The Cleveland Clinic.