What is Continuous Glucose Monitoring (CGM)?

 CGM (Continuous Glucose Monitoring) systems consist of a small and discreet wearable device that tracks your glucose, 24 hours a day, reducing the need to fingerstick while providing alerts if your levels go too high or too low. 

If you or someone you love is living with diabetes, you’re already well-versed in “the numbers”-- is your blood sugar too high (hyperglycemic) or too low (hypoglycemic)? When was the last time you tested? How much insulin do you need to administer at this meal? Did you remember to bring enough of your diabetes testing supplies in your test kit before leaving the house? And this is just the beginning of the flurry of questions you face on a daily basis. 

With so many top-of-mind diabetes-related testing questions, what happens to your quality of life? When do you get to “check out” of diabetes living and enjoy, well, simply LIVING? 

Enter continuous glucose monitoring or CGM. With a continuous glucose monitoring system, your questions will be answered without even asking. 

How Does a CGM Work?

The CGM device includes a small sensor wire that is inserted just under the skin on the back of your arm or abdomen and held in place by an adhesive backing. The sensor’s transmitter then sends glucose readings to either a separate hand-held reader/receiver or, even more conveniently, a smartphone app. 

What are the Benefits of CGM?

A CGM system is beneficial for anyone managing glucose levels due to diabetes, hypoglycemia, or other health concerns. Some CGM systems are only approved for those 18 years and older, while others are approved for children 2 years and older. 

Regardless, most CGM systems are advanced enough to allow parents or caregivers the benefit of monitoring a child and/or loved ones’ glucose levels remotely, on a smart device, even when not physically together. 

More CGM benefits include:

• Few to no fingersticks required at times
• Alert settings that notify you when glucose levels are going too high or too low – even when you or your loved one is asleep
• Using trend arrow data people living with diabetes learn how to adjust their insulin regimen. Trend arrows can predict where readings will be in the next 30 minutes
• The ability to gauge how your glucose levels are affected by your diet <link to Healthy Eating for People with Diabetes>, physical activity <link to Fitness for People with Diabetes, illness, medications and time of day 
• Reduce your A1C levels and the risk of hypoglycemia
• Get a better picture of your glucose than from your A1C
• Receive a glucose reading at regular intervals, 24 hours a day, and translate the 288 readings into dynamic data, generating glucose direction and rate of change reports
• Eliminate the guesswork in diabetes management. Doctors have much more data to interpret to better adjust your treatment and improve blood glucose levels

How Do I Get a CGM?

A CGM does require a prescription from your healthcare provider and can be covered under insurance. Your insurance coverage, however, may determine which CGM system you choose based on what qualifies within the policy. 

While paying out-of-pocket is an option, the approximate costs of CGM systems can run close to $1,000.00 for the transmitter and receiver, while sensors (with a 10- to 14-day life range) can range from $30-$120. 

As always, consult with your healthcare provider regarding your choices when it comes to using a CGM. 

Choosing the Right CGM 

There are two CGM systems available today: 

• Automatic CGM monitoring - these automatically provide glucose data to a receiver or smart phone app (every 5 minutes) and offer alarms for when glucose is rising or falling above or below the set limits. In addition, these systems allow the user to share their data with others. 
• Intermittently scanned CGM monitoring - these require manually waving the reader over the sensor to collect the information. This cgm system does not offer alarms, but you can share the data with your caregiver and it continuously measures glucose every minute and records readings every 15 minutes.

While there are pros and cons to each type of CGM available, it’s most important to consider your needs and your lifestyle, or those of your child or loved one. Discuss your needs with your healthcare provider and together you can decide upon the right CGM for your specific situation. Of course, your insurance may also determine which CGM model based on what is covered through your policy. 

What Types of CGM Systems are Available?

While different brands of CGMs may vary slightly, they all work essentially the same way. They all consist of a reader/receiver, a sensor and a transmitter, except the Eversense which has no receiver, it uses only the smartphone app with a sensor and a transmitter.  

• First, the reader/receiver is a handheld device -- or an app on your smartphone/smart device -- that receives your sensor glucose readings and shows the history of your readings and helps you see when your levels are trending up or down.
• Second, the sensor is not a needle, but a small wire inserted just under your skin that senses the change in glucose readings in the fluid that surrounds your cells. 
• Third, the transmitter, attached to the sensor, sends the information to either your reader/receiver or app. 

The types of smartphones CGM systems are compatible with may vary slightly from manufacturer to manufacturer. Smartwatches are not directly compatible with CGMs, but they can pair with your smartphone, which means when the transmitter sends information to your smartphone, your smartphone can then share it with your smartwatch. 

Top suppliers of CGM systems include Dexcom, offering the Dexcom G6 and Abbott, offering the Freestyle Libre and Freestyle Libre2, and Eversense offering the latest in technology to make managing your blood glucose safe and convenient.  

How Will a CGM Affect My Lifestyle?

While wearing a diabetic glucose monitoring medical device 24/7 may sound inhibiting both from a lifestyle and a social standpoint, wearing a continuous glucose monitor doesn’t have to be. 

First, a CGM is a discreet device held in place by an adhesive backing. Second, since diet & fitness play an inherent role in managing blood glucose levels, nothing about the CGM interferes with physical activity and exercise -- including swimming, walking, running, basketball and more. 

Since the CGM device is typically placed either on the back of the arm or the abdomen, the majority of clothing will cover the device, whether on a child, twenty-something, or a senior citizen.

When participating in physical activity, the placement and stability of the CGM can be reinforced with options such as overpatches or additional adhesives such as Skin-Tac(TM). Athletic items such as a “basketball shooting sleeve” place mild compression on the upper arm and keeps the unit in place during physical activities -- including high-contact sports such as basketball. 

And yes, swimming is an option even while using a CGM, however, keep in mind, that if you use a reader/receiver instead of an app on your smartphone, the receiver is not waterproof. 

How Do I Get Started Using a CGM?

Getting started using your CGM is a pivotal point in your diabetes management. The ability to actively manage your diabetes -- and reduce hypoglycemic episodes --  is an empowering benefit of using a CGM.

As with all medical supplies and devices, however, they must be used properly in order to derive the full benefits. Therefore, when you receive your CGM make sure to completely read its user guide. Most systems provide a USB card with videos to view how to properly insert and use the device. Every system will be slightly different.