Diabetes type 1

Continuous Glucose Monitoring (CGM)

Continuous Glucose Monitoring (CGM) involves wearing a small device that monitors the glucose levels day and night. The CGM device consists of three parts: 
  • a small sensor that sits just under the skin (which is ‘like a pump cannula’); 
  • a transmitter (this is attached to the sensor and sends data wirelessly to the display device) and 
  • a display device (this shows whether the person’s glucose levels are high, low or within range). 
CGM can be used by those on insulin pump therapy, on insulin injections, and by people taking other diabetes medication. Some CGM devices have alarms to indicate when the glucose levels are too high or too low.
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Young people we spoke to felt that using CGM has really helped with the management of their diabetes and they found it easy to use. They felt that using CGM was less time consuming and intrusive than doing blood sugar tests or the ‘finger prick test’. But they also understood that what the CGM sensor measures is the glucose in the interstitial fluid (the fluid between the cells) and not the sugar levels in the blood.
Young people said that the use of a CGM has seriously reduced the need to do finger prick tests several times a day. But they still depend on blood sugar tests when trying to understand why they are going high or low. They also understood that it is a DVLA requirement to always do a finger prick test before they drive to check if their sugar levels are within the permitted range (5 or above).
The data provided by the CGM is very useful to find out if the insulin therapy is working well. Young people said that the CGM device has made it easier to understand their glucose pattern better and identify issues such as the ‘dawn phenomenon’ which, before using the device, could have been attributed to having the wrong insulin regime rather than a simple spike in their blood glucose levels at the point of waking up. The use of CGM and knowing how their blood sugar levels are doing throughout the day and night made the young people we spoke to feel ‘more in control’ of their diabetes and ‘less scared of doing an extra insulin shot when going low’.
Young people we talked to use CGM data to produce graphs which show how their blood sugars have been doing within a certain period of time or, help to identify the periods when they are likely to go hypo or hyper. The information can also help them understand the relationship between exercise and diet and how they can affect blood sugar levels.
There are various types of CGM devices on the market but the main consideration when purchasing one seemed to be its cost. The young people we talked to said that they were self-financing their CGM and that they go for the one that is affordable and reliable. Lewis’s parents bought him the CGM device but the hospital funds the sensors. Initially, Lydia got the monitor and sensors on a clinical trial but after it finished, she decided to continue using it so now she pays for it herself.
Katie would ‘very much like’ to have a CGM but she explains that as a full-time student she can’t afford one. She knows how useful they are in helping with diabetes management and hopes to be able to afford one in the future, when she is working.
Some young people were told about CGM by their care team but most of them have got to know about CGM through social media. 
Lewis’s parents use a remote monitoring system called NightScout that allows Lewis and his parent’s access to Lewis’s CGM data via an android phone. This project is developed and maintained by an online community of parents of children with Type1 diabetes and it is free and open to all.

Last reviewed December 2017.
Last updated December 2017.


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