What Is Continuous Glucose Monitoring?
Continuous glucose monitoring (CGM) is a way to continuously track your blood sugar. It’s done using a device that has sensors put under your skin. It checks the blood sugar level in the fluid between your body cells. The sensors send readings to a monitor or your cell phone every few minutes, day and night. If you have type 1 diabetes, this data can help you spot trends in how you are managing your diabetes so you can make changes. It can also help you know if your blood sugar is on the rise or is dropping. This can help you balance food, activity, and insulin. You’ll have better control over your diabetes. Some monitors have an alarm you can set if your blood sugar reaches a certain level.
Even children can use CGM. Blood sugar readings can be sent directly to a parent’s or caregiver’s monitor or phone. It can alert parents to a child’s dropping blood sugar during the night so they can help, for instance.
Some CGM systems can eliminate the need to do finger sticks. Other CGM systems can reduce how often you need to do a finger stick. Both types still rely on standard blood sugar monitoring to make sure the system is set up (calibrated) correctly.
The sensor is usually put on the back of the upper arm. Or it may be put on the belly (abdomen) or back. In some cases, a CGM can sync with your insulin pump. Some insulin pumps can use CGM feedback information to automatically change your insulin dose.
Why might I need CGM?
CGM is a good choice if you have type 1 or type 2 diabetes and need several insulin shots every day. It’s ideal for people who need to have tight blood sugar control to keep blood sugar from getting too high or too low. It’s also helpful for people who may not recognize symptoms of low blood sugar.
CGM can help you see trends in your diabetes management. For example, you may notice that your blood sugar is lower at certain times of the day or after certain activities. You can start to make better decisions about what to eat and how much activity you can safely do. You can also find out if you need to change your insulin dose. Sometimes your healthcare provider will set you up with one of the CGM systems for a few days to see how your blood sugar patterns are doing before making any new suggestions for your care. That way you could try more than one CGM system before deciding.
Are there drawbacks to CGM?
CGM does not always replace pricking your finger and testing a drop of blood with a standard glucose meter. You may need a standard monitor to check the CGM readings before making any changes or if you have a hypoglycemic event. If you are getting your CGM results on your smartphone, be sure you can still get alerts about low blood sugars when your phone is on vibrate or on other settings.
CGM costs more than a standard monitor. Some insurance plans don’t cover the cost of a CGM.
CGM gives a lot of data. Some people may find it’s too much information. They may prefer a simpler approach. The various models of CGM machines can be quite different from each other. So be sure the training you get is for your CGM machine.
Wearing a device day and night can be a problem for some. Some people may react to the adhesive used to hold the device on the skin.
All CGMs have parts that need to be replaced on a regular basis. You will need to replace the sensor every 7 to 14 days. Check with your healthcare provider or the maker of your device about when to replace the sensor. There may be different recommendations based on which device you are using.
You may be asked to remove the sensor before getting any imaging tests such as X-rays or MRIs. If you need to remove the sensor, bring a new one with you to your appointment. Try to schedule your appointment when it's time to replace your sensor.