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What Is A1c? - Topic Overview

A1c is a test that shows the average level of blood sugar over the past 2 to 3 months. People with diabetes need to have this test done regularly to see whether their blood sugar levels have been staying within a target range. This test is also used to diagnose diabetes.

Blood for an A1c test can be collected at home or at your doctor's office. Home testing may not be an option for everyone. Check with your doctor.

  • Home testing. Home test kits for A1c are available. Using the kit, you can use a lancet (a small needle) to take a blood sample from a finger. Then, put a few drops of blood on a sample card. Place the card in an envelope and send it to a lab for testing. The lab sends the results of the test to you or your doctor.
  • Doctor's office. Some doctors, particularly endocrinologists, have blood-analysis equipment in their offices that can test hemoglobin A1c blood levels from a finger stick. The doctor can then review the results during the appointment.
  • Laboratory testing. The most accurate measurement of A1c level is done in commercial laboratories. These labs may be run by local hospitals or large health clinics, or they may be independently owned. Lab personnel check their equipment often, calibrate their machines on a regular schedule, and are monitored by federal and state regulatory authorities. A doctor's office sends the blood sample to the lab. How long it takes to get results depends on the lab. You can have the test results reported to you or your doctor.

A1c test results show your average blood sugar level over time. The result is reported as a percentage. Your goal is to keep your hemoglobin A1c level as close to the normal level as possible. Studies suggest that the lower the A1c level, the lower the incidence of diabetic complications. The American Diabetes Association (ADA) recommends keeping the hemoglobin A1c less than 7%.

The result of your A1c test can also be used to estimate your average blood sugar level. This is called your estimated average glucose, or eAG. Your eAG and A1c show the same thing in two different ways. They both help you know about your average blood sugar over the past 2 to 3 months.

The table below shows A1c with estimated average glucose.

A1c and estimated average glucose (eAG)1
Hemoglobin A1c %

Estimated average glucose (mg/dL)















A1c levels for children and teens are different. For children younger than 6 years old, the ADA recommends an A1c level less than 8.5%. In children 6 to 12 years old, the recommended level is less than 8%. And in teens, the recommended level is less than 7.5%.2

Results of A1c tests that are read at different labs vary, but standardization among labs is improving.

WebMD Medical Reference from Healthwise

Last Updated: June 26, 2013
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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If the level is below 70 or 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.

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 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.

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