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What is Continuous Glucose Monitoring (CGM)?

Continuous Glucose Monitoring (CGM) is a way to actively track glucose levels, 24/7, with little effort required by the user.


A CGM system consists of a small wearable device that actively monitors glucose at regular intervals, 24 hours a day, notifying the user of highs and lows so you can take action .


With alerts based on real-time data, CGM users have the ability to proactively manage glucose highs and lows, and gain valuable insights into the impact of meals, exercise and illness on glucose levels.


A study has shown that CGM systems may help reduce A1C levels and reduce the risk for hypoglycemia, whether users are on insulin injections or pump therapy 1

Traditional Blood Glucose Monitoring (BGM)
vs. Continuous Glucose Monitoring (CGM)


Blood glucose meters display a single glucose value at one point in time with no additional context. CGM systems, by contrast, can provide real-time, dynamic glucose information, showing not only where your glucose is, but where it's heading, and how quickly it's changing.

Traditional blood glucose meter

 If this was your meter reading, what would you do?

traditional glucose meter and Dexcom G5 mobile CGM

Dexcom G5® CGM

Would you respond differently if you know your glucose was falling rapidly?

(Double arrow down means glucose level is rapidly dropping more than 2.5 mmol/L in the next 15 minutes)

How does CGM work?

CGM users insert a tiny sensor wire just underneath the skin with an applicator. An adhesive patch holds the sensor in place so the sensor can measure glucose levels in the interstitial fluid. A small, reusable transmitter connects to the sensor and sends real-time readings wirelessly to a receiver, so you can view the information.


With the Dexcom G5® Mobile CGM System, your current glucose data can be shown on a compatible smart device$ (like a phone or a watch) using the Dexcom G5 Mobile app, or on an optional receiver.


To view a list of compatible devices, click here.

Benefits of Dexcom CGM

A1C Reduction

CGM has proven to be the best outpatient glycemic management system for reducing A1C. People with Type 1 diabetes experience an average A1C reduction of 1.3%*2

Reduced Hypoglycemia

Numerous studies have shown Dexcom CGM can decrease your time spent in
hypoglycemia1-3, and reduce the number of hypoglycemic events4. It helps to know before you’re low!

Active Monitoring at Night

The Dexcom CGM system is equipped with alerts that can warn you of approaching lows and highs. So you can sleep with less worry.

What's the difference between Continuous Glucose Monitoring (CGM) and Flash Glucose Monitoring (FGM)?


There are many differences between the Dexcom G5® Mobile CGM System and Abbott’s Freestyle Libre Flash Glucose Monitoring System.


Here are a few highlights:




Continuous Glucose Monitoring

(person can see glucose values at all times)

Flash Glucose Monitoring

(person must scan to see glucose values)

System Name DEXCOM G5 Mobile5 Freestyle Libre & LibreLink6
Indicated for Persons age 2 years and older Adults age 18 years and older who have at least 2 years of experience in self-managing their diabetes
Continuous Data Visibility Yes No, unless you scan
Can you make treatment decisions without fingerstick confirmation?

Yes, except fingerstick is required:

  • when symptoms do not match sensor readings

Yes except fingerstick is required:

  • During time of rapidly changing glucose levels (ie. can only make treatment decision if trend arrow is flat)
  • To confirm hypoglycemia
  • To confirm impending hypoglycemia
  • When symptoms do not match sensor readings
Real-Time Low/High BG Alerts


No, unless you scan

Display options

Smartphone, smart watch, standalone reciever (optional)

iPhone 7 or higher (running iOS 11 or higher)7, standalone reader

Continuous remote monitoring by family or caregiver

Yes- by using the Follow app8 on a smartphone (internet connection required) 

No, shared readings only occur when the user scans using Freestyle LibreLink on a smartphone and the follower uses the LibreLinkUp app

Calibration (with fingerstick)

Twice in the first 2 hours, then once every 12 hours

No calibration possible 

Interfering substances

(may give false readings)

Acetaminophen (ex: Tylenol)5

Ascorbic acid (ex: Vitamin C) and salicylic acid (ex: Aspirin)6

5 Dexcom G5 User Guide 
6 Freestyle Libre User Guide & Freestyle LibreLink User Guide 
7 Freestyle Librelink Smartphone Compatibility Guide 
8 Requires the Follow Ap and internet connection. Followers should always confirm readings on the Dexcom G5® Mobile app or Receiver before making treatment decisions.



Who should use CGM?

Anyone living with diabetes on intensive insulin therapy would benefit from CGM, as it offers real-time glucose levels at a glance, trending data and alerts to help users proactively manage their diabetes.


To assist both individuals with diabetes and healthcare professionals to better understand whether real-time CGM is an appropriate option for their diabetes management, an article in the Journal of the Endocrine Society9 published the following considerations:



  • Patient is 2 years of age or older
  • Currently treated by intensive insulin therapy  
  • Experiencing frequent hypoglycemia
  • Hypoglycemia unawareness
  • Excessive glucose variability
  • Varying and/or intensive activity
  • Desire to improve glycemic control
  • Understands behaviors that influence glycemic control
  • Willing and able to use real-time CGM on a nearly daily basis
  • Willing and able to learn how to use device

Is the Dexcom G5® Mobile CGM System
right for me?

Discover more details about the world’s first mobile continuous glucose monitoring (CGM) system that can help you know before you’re low.

Interested in getting a Dexcom CGM system?

If you have any questions or would like our help to check your insurance coverage, please contact us at 1-844-832-1810 or fill out our contact form and one of our Dexcom representatives will follow-up with you directly.

* MDI patients with baseline AlC = 8.5%

‡ For a list of compatible devices, click here

1 Soupal J. Petruzetkova L. Ftekac M. et al. Comparison of Different Treatment Modalities for Type 1 Diabetes. Including Sensor-Augmented Insulin Regimens. in 52 Weeks of Follow-Up· A COMISAIR Study Diabetes Technol Ther 2016.18(9)532-538

2 Juvenile Diabetes Research Foundation Continuous Glucose Monitoring Study Group. Continuous Glucos Monitoring and Intensive Treatment of Type 1 Diabetes, N Engl J Med. 2008:359(14); 1464-1476.

3 Beck RW. Riddlesworth T, Ruedy K et al. Effect of continuous glucose monitoring on glycemic control in adults with type 1 diabetes using insulin injections. The diamond randomized clinical trial. JAMA 2017;317(4) 371-378 doi 101001/Jama 201619975

4 Heinemann L Freckmann G. Faber-Heinemann G. Stefania Guerra S. Ehrmann D. Waldenmaier D. Hermanns N. Benefits of continuous glucose monitoring use in adults with type 1 diabetes and impaired hypoglycaemia awareness and/or severe hypoglycaemia treated with multiple daily insulin injections· Results of the multi-centre. randomised controlled HypoDE study. Lancet. In press.

5 Dexcom G5® User Guide

6 Freestyle Libre User Guide & Freestyle Librelink User Guide

7 Freestyle Librelink Smartphone Compatibility Guide

8 Requires the Follow App and an internet connection. Followers should always confirm readings on the Dexcom G5® Mobile app or Receiver before making treatment decisions.

9 Aleppo G. Laffel L. et al. A Practical Approach to Using Trend Arrows on the Dexcom G5 CGM System for the Management of Adults with Diabetes Journal of the Endocrine Society. December 2017 Vol 1 !ss.12. 1445-1460