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Glycohemoglobin (HbA1c, A1c)

Glycohemoglobin is a blood test that checks the amount of sugar (glucose) bound to hemoglobin. Normally, only a small percentage of hemoglobin in the blood (4% to 6%) has glucose bound to it. People who have diabetes or other conditions that increase their blood glucose levels have more glycohemoglobin than normal.

The glycohemoglobin A1c is used to diagnose diabetes. The glycohemoglobin A1c test checks the long-term control of blood glucose levels in people with diabetes. Most doctors think the glycohemoglobin A1c level is the best way to check how well a person is controlling his or her diabetes.

A home blood glucose test measures the level of blood glucose only at that moment. Blood glucose levels change during the day because of diet, exercise, and the level of insulin in the blood.

It is useful for a person who has diabetes to have information about the long-term control of blood sugar levels. The glycohemoglobin test is one blood sample every 3 to 4 months, and the test does not change with any recent changes in diet, exercise, or medicines.

Glucose binds to hemoglobin in red blood cells at a steady rate. Since red blood cells last 3 to 4 months, the glycohemoglobin A1c test shows how much glucose is in the plasma part of blood. This test shows how well your diabetes has been controlled in the last 2 to 3 months and whether your diabetes medicine needs to be changed.

The A1c level can also help your doctor see how big your risk is of developing problems from diabetes, such as kidney failure, vision problems, and leg or foot numbness. The lower your A1c level, the lower your chance for problems.

Why It Is Done

This test is done to:

  • Diagnose diabetes.
  • Check your treatment for diabetes.

How To Prepare

You do not need to stop eating before you have a glycohemoglobin test. This test can be done any time during the day, even after a meal.

How It Is Done

The health professional taking a sample of your blood will:

  • Wrap an elastic band around your upper arm to stop the flow of blood. This makes the veins below the band larger so it is easier to put a needle into the vein.
  • Clean the needle site with alcohol.
  • Put the needle into the vein. More than one needle stick may be needed.
  • Attach a tube to the needle to fill it with blood.
  • Remove the band from your arm when enough blood is collected.
  • Put a gauze pad or cotton ball over the needle site as the needle is removed.
  • Put pressure on the site and then put on a bandage.

How It Feels

The blood sample is taken from a vein in your arm. An elastic band is wrapped around your upper arm. It may feel tight. You may feel nothing at all from the needle, or you may feel a quick sting or pinch.

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WebMD Medical Reference from Healthwise

Last Updated: /2, 11 1
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.

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Your level is currently NormalHigh (hyperglycemia).Low (hypoglycemia).

If the level is below 70 and you are experiencing symptoms such as shaking, sweating or difficulty thinking, you will need to raise the number immediately. A quick solution is to eat a few pieces of hard candy or 1 tablespoon of sugar or honey. Recheck your numbers again in 15 minutes to see if the number has gone up. If not, repeat the steps above or call your doctor.

People who experience hypoglycemia several times in a week should call their health care provider. It's important to monitor your levels each day so you can make sure your numbers are within the range. If you are pregnant always consult with your health care provider.

If the level is below 70 and you are experiencing symptoms such as shaking, sweating or difficulty thinking, you will need to raise the number immediately. A quick solution is to eat a few pieces of hard candy or 1 tablespoon of sugar or honey. Recheck your numbers again in 15 minutes to see if the number has gone up. If not, repeat the steps above or call your doctor.

People who experience hypoglycemia several times in a week should call their health care provider. It's important to monitor your levels each day so you can make sure your numbers are within the range. If you are pregnant always consult with your health care provider.

Your blood sugar level is slightly high. You should call your health care provider and ask if laboratory tests to check for diabetes are needed. If you are pregnant always consult with your health care provider.

Congratulations on taking steps to manage your health.

However, it's important to continue to track your numbers so that you can make lifestyle changes if needed. If you are pregnant always consult with your physician.

Your level is currently normal. However, if you are concerned about diabetes speak with your physician. There may be other risk factors that increase your risk for diabetes.

Your level is high if this reading was taken before eating. Aim for 70-130 before meals and less than 180 two hours after meals.

Even if your number is high, it's not too late for you to take control of your health and lower your blood sugar.

One of the first steps is to monitor your levels each day. If you are pregnant always consult with your physician.

Your blood sugar level may be high, depending on when you last ate. If you have not eaten for at least 8 hours, your blood sugar should be less than 100. If you've eaten within the last 2 hours, your blood sugar should be less than 140. You should call your health care provider and ask if you need laboratory tests to check for diabetes. If you are pregnant always consult with your health care provider.

Blood sugars consistently above 180 warrant prompt medical attention.

Even if your number is high, it's not too late for you to take control of your health and lower your blood sugar.

One of the first steps is to monitor your levels each day. If you are pregnant always consult with your physician.

Your blood sugar level is high. You should call your health care provider and ask if laboratory tests to check for diabetes are needed. If you are pregnant always consult with your health care provider.

This tool is not intended for women who are pregnant.

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