hemoglobin A1c test is a lab test
used in the care of people who have
diabetes. Hemoglobin A1c is a
chemical combination of hemoglobin
and glucose. Hemoglobin is the part
of the red blood cells that carries
oxygen. Glucose is a type of sugar
in the blood that is often higher
than normal in diabetics.
Why is it
Hemoglobin A1c is an excellent way
to check how well you are
controlling your blood sugar over a
Hemoglobin A1c measurements are
important for at least two reasons.
The first is that they confirm your
daily home blood sugar monitoring
results. The second is that there
appears to be a direct relationship
between the hemoglobin A1c level and
the risk of diabetic complications.
In other words, the higher the
hemoglobin A1c percentage, the
greater the risk of developing
diabetic eye, kidney, or nervous
How do I
prepare for this test?
preparation is necessary. One of the
advantages of this test is that you
do not have to fast before you take
How is it
small tube of blood is taken from
your arm through a needle.
and how will I get the results?
may be told the results within a few
minutes of the test. Otherwise, ask
your health care provider when you
can learn the results. Ask whether
you should call for the results or
whether your provider will call you.
the results mean?
hemoglobin A1c percentage is a way
of looking at your average blood
sugar level over a period of 3
most labs a value of 4% to 6% is
normal. For diabetics the results
are usually judged as follows:
6.5%: excellent blood sugar
7% or less:
7% to 8%:
8% to 9%:
9%: poor control.
hemoglobin A1c percentage rises as
your average blood sugar level
rises. Sugar absorbed from the
digestive system circulates in the
bloodstream. Some of the sugar
combines with the hemoglobin in red
blood cells to form hemoglobin A1c.
As more sugar circulates in the
bloodstream, more hemoglobin gets
changed into hemoglobin A1c.
blood cells live 90 to 120 days.
Therefore, once sugar has combined
with the hemoglobin in red blood
cells, the hemoglobin A1c stays in
the blood for 90 to 120 days. This
means the amount of hemoglobin A1c
in your blood reflects the average
sugar concentration in your blood
over a 3-month period.
What if my
tests aren't normal?
you have not yet been diagnosed with
diabetes and your test is not
normal, you need to talk with your
health care provider about whether
you have diabetes.
you have been diagnosed as diabetic
and your test is not normal, your
health care provider will talk to
you about how to lower your blood
sugar through diet, exercise, and/or
medicine. Maintaining blood sugar
levels and hemoglobin A1c levels in
or near normal ranges will help you
avoid the complications of diabetes.
people have different types of
hemoglobin than most other people.
In these instances the test may not
be as accurate. (It also may not be
as accurate during pregnancy or if
you are anemic.) If your blood
sugars seem different on average
than your hemoglobin A1c
measurement, your doctor may
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Review Date: 6/9/01