A Continuous Glucose Monitor is a small device worn under the skin that uses interstitial fluid to monitor blood glucose levels. It then transmits readings to a receiver and allows a person with diabetes to have a guide to what blood glucose levels may be at a given time and whether they are expected to rise or fall in the near future.
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What is the difference between traditional glucose testing and using a Continuous Glucose Monitor?
Glucometers are portable devices that read glucose levels from a blood sample that is placed on a tiny test strip. Test strips are discarded after a single-use. Some meters store a limited number of glucose results in memory. The results can be downloaded into a computer.
A glucose sensor, on the other hand, is a tiny electrode that is inserted under a patient’s skin (subcutaneous tissue) that continuously records glucose levels around the clock. The sensor is worn for between three to seven days before it is discarded and replaced by the patient. Glucose readings are transmitted to a monitor, smartphone or insulin pump where the values are displayed. Trend reports and charts can be viewed after data is downloaded to a computer.
Download our free CGM/Flash monitoring systems comparison sheet.
Types of Continuous Glucose Monitors
Dexcom G7®
The Dexcom G7® is the latest version of Dexcom’s Continuous Glucose Monitor. This system has received a CE-mark, allowing Dexcom to sell the device to people with diabetes in Europe. It has not yet been approved for sale in any North American markets.
Here are some of the new features of the G7®:
- 60 percent smaller and round in shape. This new design allows it to be “inserted on the back of the upper arm, the abdomen, or, for children ages 2-17, on the upper buttocks. It can also be inserted using only one hand.” according to the folks at diaTribe.
- 30-minute sensor warm up.
- Improved alert settings for enhanced discretion
Dexcom G6®
The Dexcom G6® is the most updated version of the Dexcom® CGM. This product also uses Bluetooth technology but now has sensors that last 10 days. This sensor is water-resistant. It no longer requires calibration but users can still choose to enter a calibration if they would like to or feel that the sensor seems inaccurate. The Dexcom G6® still requires a 2-hour warm-up period. The “urgent low soon” alarm will alert the user when blood glucose is dropping rapidly and is expected to cross the low threshold. It also has a new easy-to-use,
It continues to work with smartphones as a standalone device, and with the latest US version of the Tandem insulin pump.
Dexcom has also signed agreements with OmniPod and Ypsomed on possible future integrations.
Enlite™ glucose sensor and MiniLink™ transmitter
The Enlite sensor has an electrode that inserts just under the skin to measure glucose values. It works with the Guardian™ 2 link transmitter to send glucose information to your MiniMed™ insulin pump.
This sensor is smaller and more flexible than previous Enlite sensors making it more comfortable to wear. Because the insertion needle is now hidden, the insertion process is much easier.
The Guardian™ 2 link transmitter can store up to 10 hours of data. This continuous glucose monitoring system offers real-time glucose monitoring that is sent to the insulin pump very 5 minutes.
Eversense E3®ontinuous Glucose Monitor System
The Eversense E3 is the latest version of the implantable glucose sensors from Senseonic. This new system will allow you to wear your CGM for up to 180 days without having to change out the sensor and without sacrificing accuracy. At its release, the Eversense E3 is the most accurate continuous glucose monitoring system in North America.
The sensor must be implanted by a medical professional.
You can read all about the features and how to get your Eversense E3 in our article linked below. This system is currently only approved for sale in the US.
Freestyle Libre
Flash monitoring systems do not continuously transmit readings to a monitor, smart device or insulin pump. Readings are transmitted when the system reader is passed over the receiver.
The Libre Flash Monitoring system is convenient and discreet. It requires no calibration. With each scan you get the current glucose reading, the last 8 hours of glucose data and an arrow showing the direction glucose readings are heading. These sensors are also safe to wear in the pool or shower.
Libre does not currently work with any insulin pump. Talks are ongoing with Tandem Diabetes Care and Insulet to change this.
Freestyle Libre 2
The Libre 2 is an integrated continuous glucose monitoring system cleared for use in Europe, Canada and in the USA for adults and children 4 years and older. It continually transmits glucose data every minute to the receiver. Users can now set the system to send alarms when their glucose is too high or too low without having to first scan the sensor.
This system is approved to work with insulin pump and automated insulin dosing systems.
Read more about the Libre2 here.
FreeStyle Libre 3 system
Abbott has announced that the FreeStyle Libre 3 system has received CE mark for people with diabetes in Europe. The Libre 3 has the smallest, thinnest sensor on the market world’s smallest being about the size of two stacked U.S. pennies.
The new FreeStyle Libre 3 will provide 14 days of continuous real-time glucose readings automatically delivered to a person’s smartphone every minute. The sensor can be easily applied with a one-piece applicator.
According to the press release, the new system is also designed to be more sustainable for the environment, including a 41% reduction in plastic use and 43% decrease in carton paper.
Guardian™ Connect System
According to Medtronic, the Guardian Connect System is a standalone continuous glucose monitoring system that connects directly to select Apple devices using Bluetooth technology. It provides continuous glucose information and alerts you up to 60 minutes in advance of highs and lows.
You can learn more about their system on the Guardian Connect System website.
How to decide if a CGM or Flash system is right for you
Deciding which system you should use or even if you want to be hooked up to a device at all is a very personal decision. You may want to consider things like
- Cost
- Sensor size
- Life of a sensor
- Number of times you have to calibrate the system
- Can you share your data with others?
Read the pros and cons of a Continuous Glucose Monitoring System.
Using a CGM to establish Time in Range
Time in Range looks at the amount of time that you maintain blood sugars between set parameter for a period of 14-days. While this can be done using a glucometer, the most accurate results involve using a CGM to monitor for unseen highs and lows.
You can learn more about Time in Range in the article below.
Studies on the effectiveness of Continuous Glucose and Flash Monitoring Systems
18 month comparison of Medtronic Enlite and Dexcom4
Compare CGM Features
Download the free PDF to compare Continuous Glucose Monitors
