***The ABCs of A1C Testing* . . . The Best Test of Blood Sugar**
**Control for People with Diabetes**

**What is the A1C test?**

The A1C test (also called H-b-A-one-c) is a simple lab test that shows
the average amount of sugar (also called glucose) that has been in a
person's blood **over the last 3 months.**

The A1C test shows if a person's blood sugar is close to normal or too
high. It is the **best test** for a health care provider to tell if a
person's blood sugar is under control.

**What does this test measure?**

Sugar in the bloodstream can become attached to the in (the part of the
cell that carries oxygen) in red blood cells. This process is called
glycosylation (pronounced gli-kos-a-lay'-shen). Once the sugar is
attached, it stays there for the life of the red blood cell, which is
about 120 days. The higher the level of blood sugar, the more sugar
attaches to red blood cells. The A1C test measures the amount of sugar
sticking to the red blood cells. Results are given in percentages.

**Why do more people need to know about this test?**

The findings of a major diabetes study, the Diabetes Control and
Complications Trial (DCCT), have shown just how important the A1C test
is. The study showed that lowering the A1C number can delay or prevent
the development of serious eye, kidney, and nerve disease in people with
diabetes. The study also showed that lowering A1C levels by **any**
amount improves a person's chances of staying healthy.

**When should this test be done?**

All people with diabetes should have an A1C test at least twice a year.
People with diabetes should get the test more often if their blood sugar
stays too high or if their health care provider makes any change in
their treatment plan.

**How is the A1C test done?**

This test is usually done in a health care provider's office. To do the
test, a small sample of blood is taken. The blood sample is sent to a
laboratory for testing, and the laboratory sends the results to the
patient's health care provider.

**Where does self-monitoring of blood glucose fit in?**

Self-monitoring of blood glucose is also very important. A finger-stick
test using a blood glucose meter measures the actual level of sugar in
the blood **at the time of the test.** The meter reading is reported in
milligrams per deciliter (mg/dl).

Self-monitoring of blood glucose helps people with diabetes see how
food, physical activity, and diabetes medicine affect their blood sugar.
The readings from these tests can help people with diabetes manage their
disease day by day or even hour by hour. The readings can also tell them
when their blood sugar is too low or too high, so they can work with
their health care provider to change their treatment plan.

All people with diabetes need regular A1C tests. Most people with
diabetes also need to self-monitor their blood glucose to get a complete
picture of blood sugar control. Self-monitoring blood glucose gives a
snapshot of control **at the time of the test,** while the A1C test
gives the big picture of control **over the past 3 months.** Together,
these tests tell a patient and his or her health care provider whether
the patient's blood sugar is under control.

**What does an A1C test result mean?**

The A1C goal for people with diabetes is **less than 7 percent**. The
DCCT findings showed that people with diabetes who keep their A1C levels
close to 7 percent have a much better chance of delaying or preventing
diabetes problems that affect the eyes, kidneys, and nerves than people
with A1C levels 8 percent or higher. A change in treatment is almost
always needed if a person's A1C is over 8 percent. But, if people with
diabetes can lower their A1C number by **any** amount, they will improve
their chances of staying healthy.

**How does the A1C relate to readings from self-monitoring of blood
glucose?**

People with high daily blood sugar readings most of the time will
usually have a high A1C test result. To maintain an A1C level less than
7 percent means that the blood sugar should rarely go above 150 mg/dl on
any self-monitoring blood glucose test performed before meals during the
previous 3 months. The blood sugar also should not drop below 60-70
mg/dl, or low blood sugar occurs.

**How can people with diabetes keep their A1C at less than 7 percent?**

Staying in control of diabetes over a prolonged period of time requires
following a recommended meal plan, sticking to a physical activity
program, taking prescribed diabetes medicines, self-monitoring of blood
glucose if recommended, and consulting a health care provider often.
When a patient has a high A1C test result, a health care provider can
work with the patient to identify what is causing high blood sugar by
examining the patient's record of self-monitoring blood glucose. Common
causes of high blood sugar include eating too much food or eating the
wrong foods, lack of physical activity, stress, a need to change
medicines, and infection or illness. By finding the source of the
problem, a health care provider can decide if and how to change a
patient's treatment plan to meet the A1C goal of less than 7 percent.

**How can people with diabetes use their A1C test results?**

When people with diabetes know the results from their A1C test, they can
take an active role in their diabetes management. A **high A1C** is one
that is greater than 8 percent. People with diabetes who have a test
result that is greater than 8 percent need to work with their health
care provider to change their treatment plan.

An A1C test result that is **close to normal** is one that is less than
7 percent. When people with diabetes have a test result that is less
than 7 percent, their treatment plan is probably working and it is
likely that their blood sugar is under good control.

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