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There are different types of glucose monitors that you can use to check your glucose (sugar) level at home. These include:
A rtCGM has several parts. You wear one part—the sensor—against your skin. It has a tiny sensor that stays under your skin. The sensor is constantly reading the blood glucose level of the fluid between your cells (interstitial). The sensor sends this information to the other part of the monitor (a wireless receiver or smartphone app). Some insulin pumps include an rtCGM receiver that is built into the pump.
An isCGM also has several parts. You wear one part—the sensor—against your skin. It has a tiny sensor that stays under your skin. The other part is a wireless reader device that displays your glucose level when the sensor is scanned with the reader device or smartphone app. You can get a reading when you need it (on demand). There can be a 5 to 15 minute difference between an interstitial glucose level and a blood glucose level. If your glucose levels are not changing quickly there may be little difference between your interstitial glucose level and your blood glucose level. But when your glucose level is changing quickly, like after eating a meal or treating a low blood glucose, there can be delays in getting an accurate reading from your CGM.
At any time, you can look at the receiver or smartphone app and see your glucose level. You can see if your level is going up or down—and how fast. You can see the trends and patterns of your glucose levels. Some monitors use text messages, apps, and websites to show you trends and patterns.
Some monitors let you add notes of when you eat, exercise, and take medicine. That way you can see how those activities affect your blood glucose levels throughout the day and night.
All this detailed information gives you and your diabetes care team a better idea of your treatment needs.
Some rtCGMs and isCGMs need you to poke your finger and use your CBG meter to confirm what the monitor is telling you. Anytime your rtCGM or isCGM does not display a value, or if the reading does not match your symptoms, it is recommended that you verify the rtCGM or isCGM result with your finger poke CBG meter to make sure your sensor is reading accurately.
An rtCGM or isCMG is constantly measuring your blood glucose levels. This information helps some people who have diabetes make decisions about what to eat, how or when to exercise, and how much medicine to take.
Some rtCGMs and isCGMs have an alarm feature to alert you if your blood glucose level is quickly going up or down, or if you have a blood glucose level out of your target range. This is helpful for people who have problems knowing when they have low blood glucose (hypoglycemic unawareness). Some monitors can be set up so that parents, partners, or caregivers can be alerted when your blood glucose is dropping quickly while you are asleep.
CGM technology is always changing and getting better. Here are some things to know about most CGMs. These may not apply to all systems.
Adaptation Date: 9/21/2022
Adapted By: Alberta Health Services
Adaptation Reviewed By: Alberta Health Services
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