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If You Have Diabetes, Know Your Blood Sugar Numbers

Taking control of your diabetes can help you feel better and stay healthy. Research shows that keeping your blood glucose (blood sugar) close to normal reduces your chances of having eye, kidney, and nerve problems. To control your diabetes, you need to know your blood glucose numbers and your target goals.

There are two different tests to measure your blood glucose:
1. The A1C test (pronounced A one C), which used to be called hemoglobin A1C, measures your average blood glucose level over the last 3 months. It is the best way to know your overall blood glucose control during this period of time.

2. A blood glucose test you do yourself, using a drop of blood and a meter, measures your blood glucose at the time you check it.

You and your health care provider need both tests to get a complete picture of your blood glucose control.

What is the A1C test?
The A1C test is a simple lab test that measures your average blood glucose level over the last 3 months. Your health provider takes a small blood sample to test your A1C. But just to be clear the A1C is not the same as measuring all you blood tests with your meter over a period of three month and calculating the average. The A1C test measures the amount of hemoglobin glycated in your blood. Hemoglobin is found inside red blood cells. Its job is to carry oxygen from the lungs to all the cells of the body. Hemoglobin, like all proteins, links up with sugars such as glucose.

When you have diabetes you have too much sugar in your bloodstream. This extra glucose enters your red blood cells and links up or glycates with molecules of hemoglobin. The more excess glucose in your blood, the more hemoglobin gets glycated. The A1C test measures the percentage of hemoglobin glycated in the blood. The result is an overview of your "average" blood glucose control for the past few months.

Suppose your blood sugar was high last week. More glucose hooked up (glycated) with your hemoglobin. This week, your blood glucose is back under control. Still, your red blood cells carry the 'memory' of last week's high blood glucose in the form of more A1C. This record changes as old red blood cells in your body die and new red blood cells (with fresh hemoglobin) replace them. The amount of A1C in your blood reflects blood sugar control for the past 120 days, or the lifespan of a red blood cell.

In a person who does not have diabetes, about 5% of all hemoglobin is glycated. For someone with diabetes and high blood glucose levels, the A1C level is higher than normal. How high the A1C level rises depends on what the average blood glucose level was during the past weeks and months.

You should have had your A1C level measured when your diabetes was diagnosed or when treatment for diabetes was started. To watch your overall glucose control, your doctor should measure your A1C level at least twice a year. This is the minimum. There are times when you need to have your A1C level tested about every 3 months. If you change diabetes treatment, such as start a new medicine, or if you are not meeting your blood glucose goals, you and your doctor will want to keep a closer eye on your control.

Why should I have an A1C test?
The A1C test is the best test for you and your health care team to know how well your treatment plan is working over time. The test shows if your blood glucose numbers have been close to normal or too high. The higher the amount of glucose in your blood, the higher your A1C result will be, increasing your chances for serious health problems.

What is a good A1C goal?
You and your health care team should discuss the A1C goal that's night for you. For most people with diabetes, the A1C goal is less than 7. If your A1C number is less than 7, your care plan is probably working and your blood glucose is under good control. An A1C number higher than 8 means that you have a greater chance of eye disease, kidney disease, or nerve damage. Lowering your A1C number by any amount can improve your chances of staying healthy. If your number is higher than 8, ask your health care provider about changing your treatment plan to bring your A1C number down.

Level of Control A1C
Normal 6 or less
Goal 7 or less
Take Action 8 or more

What about home testing for A1C?
Home testing for A1C is now possible and some people with diabetes may find it helpful to use this test. Be sure to do it properly and discuss the results with your doctor.

Checking Your Own Blood Glucose:
The Best Test for Day to Day Glucose Control
Checking your blood glucose with a meter helps you see how food, physical activity, and medicine affect your blood glucose. The readings you get can help you manage your diabetes day by day or even hour by hour. Always keep a record of your test results and review it with your health care provider. can help you upload your reading automatically directly into the service and delivering for you the reports you need so your health care provider can better see how your current plan is affecting your health.

Measuring your sugar daily is extremely important and it is easy to do. Use a drop of blood and a meter to measure your blood glucose level. Be sure you know how to do the test properly.

Set your blood glucose goals with your health care provider. Blood glucose goals for most people with diabetes when self testing are:

Normal Ranges
Before breakfast (fasting), lunch, supper, or snacks 90-130
Two hours after meals <160
Bed time 110-150
A1C <7%

How often should I check my blood glucose?
Self tests are usually done before meals and/or at bedtime. Ask your health care provider when and how often you need to check your blood glucose.

If I test my own blood glucose, do I still need the A1C test?
Yes. The results of each test help you and your health care team to manage your diabetes and get a complete picture of your diabetes control.

Does my insurance pay for self testing supplies and education?
At least 44 states have passed laws that require insurance coverage of self testing supplies and diabetes education. Check your coverage with your insurance plan. Medicare covers most of the cost of diabetes test strips, lancets (needles used to get a drop of blood), and blood glucose meters for people who have diabetes. Ask your health care team for details about Medicare's coverage of diabetes supplies as well as diabetes education and nutrition counseling and visit the Medicare website at

How do blood glucose self testing Level Test Average results compare with A1C test results?
Here's a chart to show you how your blood glucose testing results are likely to match up with to your A1C results. As the chart shows, the higher your self testing numbers are over a 3 month 7 period, the higher your A1C result is going to be.

A1C Level Blood Glucose
Test Average
5 80
6 120
7 150
8 180
9 210
10 240
11 270
12 300

What other numbers do I need to know to control my diabetes?
People with diabetes are at high risk for heart attack and stroke. Be smart about your heart and take control of the ABCs of diabetes: A1C, Blood pressure, and Cholesterol.

Take Control of Your Blood Glucose

  1. Talk to your health care provider about your A1C and your self testing blood glucose targets.
  2. Ask for an A1C test at least twice a year.
  3. Ask your health care team what your A1C number is, what it means, and what you need to do to reach your A1C goal.
  4. Check your own blood glucose as often as needed and go over the results with your doctor and other health care team members.
  5. To keep your blood glucose under control, eat the right foods in the right amounts, get regular physical activity, and take prescribed medicines.
  6. Ask your health care provider about your blood pressure and cholesterol numbers and what your target goals should be.

Control your diabetes — will help you manage it

Source: The National Diabetes Education Program is a partnership of the National Institutes of Health, the Centers for Disease Control and Prevention, and over 200 private and public organizations. For more information, visit

NIH Publication No. 98 4350 (NDEP 10)

Adapted by Editorial Staff, May 2002
Last update, July 2008



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