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Diabetes Health Center

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Continuous Glucose Monitoring - Topic Overview

When you test your blood sugar, you learn your blood sugar level at that time. But you can't tell what's happening to your blood sugar the rest of the time-especially overnight. A continuous glucose monitor, or CGM, can do that for you. It reports on your blood sugar at least every 5 minutes, day and night. And it sounds an alarm if it sees that your levels are headed out of range.

How does a continuous glucose monitor work?

A CGM has three parts. You wear one part-the sensor-against your skin. It has a tiny needle that stays under your skin. A transmitter is attached to the sensor and constantly reads your blood glucose level. It sends this information to the other part of the monitor, a wireless receiver that you (or a caregiver such as a parent) wear on your belt or in your pocket.

At any time, you can look at the receiver and see what your glucose level is. You can see if your level is going up or down-and how fast. You can download the information to your computer and see the trends and patterns of your glucose levels.

You note on the receiver when you eat, do exercise, and inject insulin. That way you can see how those activities affect your blood sugar throughout the day and night.

All this detailed information gives you and your doctor a better idea of what your treatment needs are.

Continuous monitors are not as accurate as standard meters. At least once or twice a day, depending on the type of monitor you buy, you will have to prick your finger and use your standard meter to confirm what the CGM is telling you.

What are the benefits?

A CGM is constantly measuring your blood sugar. This information helps some people who have diabetes make decisions about what to eat, how to exercise, and how much medicine to take. Using a CGM has been shown to give people with type 1 diabetes better control of their blood sugar levels, with fewer low blood sugar emergencies.

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