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Understanding the A1C test

The A1C test is a simple blood test that measures average blood sugar levels over a period of time. It is used to diagnose both prediabetes and diabetes, and it can help you and your healthcare team in managing your diabetes. The A1C test, combined with other measures recommended by your care team, are important to monitor along your diabetes journey.

How does it work?

The A1C test gives you a high-level view by providing a snapshot of your average blood sugar levels over the past three months. More specifically, the A1C test measures the percentage of hemoglobin proteins in your blood that are glycated (covered in sugar).1 The A1C test result is reported as a percentage. The higher the percentage, the higher your blood glucose levels have been. Below is a general overview. However, you should note that it is not intended to be a substitute for professional medical advice, diagnosis, or treatment. You should always seek the advice of your healthcare provider with any questions you may have regarding the A1C test and questions otherwise related to your medical condition.

patient reviewing test results with doctor

Your healthcare provider will recommend how often you need the A1C test, but usually you’ll have the test at least twice a year. If your management or treatments change, you may need to get an A1C test more often.

Breaking down the numbers

How you interpret your A1C test results can vary depending on your age and other factors. There’s no "one size fits all" and your target may be different from someone else’s. Most adults living with diabetes aim for an A1C result that is less than 7 percent. When the percentage is higher, it indicates that your blood sugar levels have been high over the previous three months, and adjustments should be made.

A1C percentages can also be used to diagnose diabetes. A1C levels between 5.7 and 6.5 percent are within the prediabetes range. Anything above 6.5 percent is in the diabetes range.2

Preparing for the test

As it is a simple blood test, you can eat and drink normally prior to checking your A1C. Your doctor may extract blood via a vein in your arm, or by a prick of the finger. Some doctors may be able to provide same-day results, though in most cases your blood will be sent to a lab for analysis.

A1C is only one metric

A1C is an important tool, but it doesn’t replace regular blood sugar testing at home. Blood sugar goes up and down throughout the day and night, which isn’t captured by your A1C. With access to blood glucose meters and continuous glucose monitors, knowing the day-to-day variance is also important.

If you’re reaching your A1C goal but have highs or lows, keep track and share the results with your doctor so you can make changes to your treatment plan if needed.

Remember, you are an individual with individual goals and needs. Working with your diabetes care team to set specific goals is very important.

Other resources accessed for this review:

1. A1C Test. The Mayo Clinic Page. https://www.mayoclinic.org/tests-procedures/a1c-test/about/pac-20384643. Accessed 20AUG2021
2.Understanding A1C. There American Diabetes Association Page. https://www.diabetes.org/a1c. Accessed 20AUG2021

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