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Continuous glucose monitoring and flash glucose monitoring

  • There are currently two CGM systems available in Australia; one produced by Medtronic and the other by Dexcom.

    An NDSS summary of the available CGM devices

    Another form of glucose monitoring is FGM (Libre 1 and Libre 2)

    Access to fully subsidised CGM and FGM is available to eligible people with type 1 diabetes.

    For further information re the NDSS subsidy

    What is CGM and FGM?

    CGM/FGM works by a sensor, inserted under the skin which measures the glucose in interstitial fluid. A transmitter connects to the sensor and transmits the sensor glucose (SG) readings to a mobile phone, insulin pump or a Libre glucose meter. Interstitial glucose and blood glucose are similar, but not exactly the same.

    Some CGM systems require calibrations to keep them accurate. Despite using this technology and the different requirements for calibrations in the various FGM/ CGM systems, blood glucose level (BGL) checking still has an important role in diabetes care.

    CGM / FGM importantly show the trends in glucose levels and provides a directional arrow to indicate if the glucose is stable, rising or falling. When BGLs are high, low or quickly changing (e.g., after giving insulin, eating, hypoglycaemia treatment and exercise) there can be a significant difference between the SG reading and the BGL

    When glucose levels are stable the SG is more likely to reflect the BGL, however whenever things are not stable (eg with food intake, exercise etc) there can be significant differences between the SG levels in the interstitial fluid and the actual glucose level is in the blood. Of course your BGL is really what is critical in determining your immediate well-being.

    Before starting CGM or FGM it is important to understand that these systems are used in addition to, but do not completely replace, blood glucose level (BGL) checking using finger pricks. 

    Both the Dexcom G5 and the Medtronic CGM systems require calibrating. This is done by performing a blood glucose on a meter as you have always done. Depending on the system of choice calibrations with a BGL are required between 2 - 4 times / day. For the CGM sensor glucose readings are taken by the system every 5 minutes and displayed on a reader or phone device. The Dexcom G6 is currently only subsidised by the NDSS for Tandem T:Slim users (if not using a Tandem T:Slim insulin pump, the system needs to be purchased from AMSL). 

    The FGM system includes the Libre 1 and Libre 2 systems. These systems do not require calibrating although BGL checking still required. The FreeStyle Libre FGM system is indicated for measuring interstitial fluid glucose levels in people (age 4 and older) with diabetes mellitus. Information is received by swiping either the Libre meter or the mobile phone to receive the sensor glucose reading. The Libre 2 system now includes optional alarms to be set for the person with diabetes and their caregiver. 

    CGM/FGM sensors vary in terms of how long they last. Depending on the brand, under ideal conditions they will last between 7-14 days.

    For more CGM/FGM information:

    Dexcom G5 

    Freestyle Libre 2 

    Device compatibility for Dexcom G5


    Device compatibility for Medtronic Guardian Connect 

    Dexcom G6

    RCH process for starting CGM:

    If you wish to access CGM under the NDSS subsidy, please review the different products above and decide which is best suited to your child.

    Please complete the NDSS form and return to

    You will join a wait list and receive correspondence from the RCH diabetes team when the time comes to be offered an appointment for commencement and education about the CGM.

    Currently appointments continue to be offered via Telehealth, however if you wish to have a face to face appointment, please discuss this with the diabetes team.

    At the time of arranging the appointment, you will be asked to sign a diabetes management plan which is a requirement of accessing the CGM under the NDSS subsidy.

    Flash Glucose Monitoring (FGM)?

    FGM is similar to CGM, except that you have to scan the sensor with a reader, smartphone or smart device to get your reading. The Libre 2 system now includes optional alarms to be set for the person with diabetes and their caregiver. 

    FGM information

    Instructions to get started with Libre 2 FGM

    Step 1 forms to complete: 

    Email both the management plan AND NDSS form to

    Step 2 completed forms:

    A credentialled diabetes educator will sign the forms and send the form to NDSS.  

    You will get an invitation to join RCH Libre View.

    Accepting this invitation means that the team at RCH can view your data at appointments and in between clinic appointments to help with dose adjustments. 

    Step 3 ordering supplies:

    The components of the FGM System are:

    Libre 2 components

    NDSS Next Steps Guide. The NDSS Subsidy ‘Next Step Guide’ is a guide to provide information on how to access the subsidy once the NDSS have approved the child’s use of the Libre. Please read this and follow the process – you will also see that you can order a complementary BGL meter/reader through the website. IMPORTANTLY: Please ensure you select Freestyle Libre 2 

    NDSS will email you with confirmation to commence the Libre. Please call if you have not heard from them within a week of receiving the LibreView invite from RCH.

    • Go to your local NDSS pharmacy and order sensors for the Libre 

    • The sensors need to be changed every 14 days

    Once NDSS confirmation is received go to Scan My Sensor to order a Freestyle Libre reader. The reader can be used to swipe the senor as well as do a fingerprick to check glucose and ketones levels. 

    Step 4 setting up your Libre account:

    The apps to download to be able to see your Libre information are: 

    LibreLink is the app used by the person with diabetes. By using this app on your phone you can scan to get your current sensor glucose.  

    LibreLink App

    You can either scan with your Libre reader or via the app. Downloading the reader to LibreView (see below) is important as well because it allows all of your glucose readings to be viewed alongside the scanned readings. 

    Both the reader and app will give you the current sensor reading when you scan along with a directional arrow as to where your levels are heading. 

    Libre LinkUp is the app a caregiver can put on their phone to view the information. Scans done via the mobile phone can then be seen on the Libre LinkUp app. 


    Step 5 how to insert your sensor: 

    When you have picked up a sensor from the pharmacy and you have received your Libre meter. Go to the Abbott website to learn how to insert your sensor.

    Sensor insertion instructions

    Written step by step instructions

    • When your Libre is inserted scan the reader or phone to start the 1 hour warm up period. To link both devices to your new sensor, scan the reader before the mobile phone.  
    • Sensors are inserted on the arm and are changed every 14 days. Ensure you rotate sensor insertion sites with each new sensor insertion. 
    • Insulin should not be injected in the site where your sensor is located. 

    Step 6 setting alerts:

    These are optional alerts to be notified if the levels go up or down. We recommend setting the low glucose alert art 3.8mmol/L. Remember to always do a confirmatory blood glucose check if a scan states you are low.

    We recommend to keep the high glucose off. Having a high alert on can result in alarm fatigue and ignoring the alarms you need to react to. You will be able to view where you are going high when you scan your Libre and when you are viewing your trend graphs. 

    Step 7 viewing your data using LibreView:

    A commitment should be made to view your Libre data and BGs every week. Libre View will show you the patterns in your readings by filling the gaps in between the BG checks and scans that you have been doing. You can view the day by day information to see where the patterns are evident. When wearing the device most of the time it will also tell you what your Time in Range is, as well as give you an estimated HbA1c. This is useful information to help know if your readings have mostly been in range or if adjustments are needed.

    LibreView is the website to view what has been happening. A diabetes educator will send you an invitation to join the RCH LibreView account or you can follow the below steps to link to the RCH diabetes clinic. This means when you come to clinic or you contact the diabetes team for dose support glucose readings can be viewed. Uploads are done automatically from the mobile phone, remember to also upload the reader so that your BG checks with the cord provided will appear on the upload as well. 

    Sharing with the RCH Diabetes Clinic - ID code 0393456661. Log into your LibreView Account. Go to your settings section and select Account Settings. Click on My Practices and enter your healthcare provider's 'Practice ID Code' and click Add.  

    For data privacy, please see the back of the Flash management plan and be sure to read the Libre consumer agreement when you sign-up.  

    Links to CGM/FGM websites and resources

    CGM/FGM videos and resources