Key Takeaways
- CGMs continuously measure glucose in interstitial fluid, giving readings every 1–5 minutes
- The NDSS subsidises CGM consumables for eligible Australians with type 1 diabetes
- Dexcom G7 and Abbott FreeStyle Libre 2 and 3 are the main systems available in Australia
- CGM data is reported as "time in range" — a more complete picture than HbA1c alone
- CGMs are increasingly accessible for type 2 diabetes but NDSS funding criteria differ
Continuous glucose monitoring (CGM) has transformed diabetes management over the past decade. Rather than relying on snapshot fingerprick readings, CGMs provide a continuous stream of glucose data — typically every one to five minutes — giving people with diabetes and their healthcare teams an unprecedented level of insight into how blood glucose behaves throughout the day and night.
This guide explains how CGMs work, which devices are currently available in Australia, who can access government-subsidised CGM supplies, and what to expect when starting on a CGM system.
How CGMs Work
A CGM system consists of three main components:
- A small sensor inserted just under the skin (usually on the upper arm or abdomen) that measures glucose levels in the interstitial fluid — the fluid that surrounds cells in body tissue
- A transmitter (sometimes built into the sensor) that wirelessly sends readings to a receiver or smartphone
- A display device — either a dedicated receiver, a smartphone app, or compatible insulin pump — that shows real-time glucose readings, trends and alerts
It is important to note that CGMs measure glucose in interstitial fluid, not directly in the blood. There is a natural lag of approximately 5–15 minutes between a change in blood glucose and the corresponding change appearing in interstitial glucose readings. This is why CGM readings can sometimes differ slightly from fingerprick readings, particularly when glucose levels are changing rapidly.
CGM vs traditional fingerprick testing
A traditional blood glucose meter gives you one reading at a single moment in time. A CGM gives you a reading every few minutes, day and night — including while you sleep. This allows you to see trends, catch overnight lows, and understand how specific foods or activities affect your glucose over hours rather than moments. The total picture this creates is far richer than any number of fingerprick tests could provide.
CGM Devices Available in Australia (2025)
The two main CGM systems available in Australia are made by Abbott and Dexcom. Both are TGA-approved and widely used.
Abbott FreeStyle Libre 2 and Libre 3
The FreeStyle Libre system uses a small round sensor worn on the back of the upper arm. The Libre 2 sensor lasts 14 days, while the newer Libre 3 — a smaller, slimmer sensor — also lasts 14 days and sends automatic glucose readings to a smartphone every minute.
Key features of the FreeStyle Libre systems include:
- No fingerprick calibration required
- Optional real-time alarms for high and low glucose (Libre 2 and 3)
- Automatic data sharing with caregivers or healthcare providers via LibreLinkUp
- Compatible with the LibreLink smartphone app (iOS and Android)
Dexcom G7
The Dexcom G7 is a fully integrated sensor-transmitter worn on the upper arm or abdomen. It lasts 10 days (with an optional 12-hour grace period) and sends real-time readings every 5 minutes to a compatible smartphone or receiver.
Key features of the Dexcom G7 include:
- Customisable glucose alerts with predictive low glucose alarms (alerting before a hypo occurs)
- Direct integration with several insulin pump systems for closed-loop (automated insulin delivery) therapy
- Share feature allowing real-time data sharing with up to 10 followers
- 30-minute warm-up time (shorter than previous generations)
| Feature | FreeStyle Libre 2 | FreeStyle Libre 3 | Dexcom G7 |
|---|---|---|---|
| Sensor wear time | 14 days | 14 days | 10 days (+12hr grace) |
| Reading frequency | On scan or every minute (alarms) | Every 1 minute (automatic) | Every 5 minutes |
| Calibration required | No | No | No (optional) |
| Real-time alarms | Yes | Yes | Yes (with predictive) |
| Pump integration | Limited | Limited | Yes (multiple pumps) |
| NDSS subsidised | Yes (eligible users) | Yes (eligible users) | Yes (eligible users) |
NDSS Subsidies: Who Can Access Subsidised CGM?
The National Diabetes Services Scheme (NDSS) subsidises CGM consumables for eligible Australians, significantly reducing the out-of-pocket cost. As of 2025, NDSS CGM access is available for:
- All Australians with type 1 diabetes who are registered with the NDSS
- Australians with type 2 diabetes who use insulin and meet specific criteria (including those at high risk of hypoglycaemia or with impaired hypoglycaemia awareness)
- Pregnant women with type 1 diabetes or on insulin for gestational diabetes
- Children with any form of diabetes who use insulin
The subsidised cost varies depending on the device and your eligibility. NDSS registration is required. You can register or check your eligibility at the NDSS website or by calling 1800 637 700.
CGM access has expanded significantly
NDSS CGM eligibility has broadened considerably over recent years. If you were previously told you didn't qualify, it is worth checking again — the criteria have changed, and more Australians now qualify for subsidised access than at any previous time.
Understanding Time in Range (TIR)
One of the most valuable outputs of CGM data is time in range (TIR) — the percentage of time your blood glucose stays within a target window, typically 3.9–10.0 mmol/L for most adults with diabetes.
The internationally agreed TIR targets for adults with type 1 or type 2 diabetes are:
- Time in range (3.9–10.0 mmol/L): Greater than 70% of the day
- Time below range (<3.9 mmol/L): Less than 4%
- Time in hypoglycaemia (<3.0 mmol/L): Less than 1%
- Time above range (>10.0 mmol/L): Less than 25%
TIR is increasingly used alongside HbA1c as a measure of glucose management quality, because it captures the variability and pattern of blood glucose — not just the average. Two people with the same HbA1c can have very different TIR profiles, reflecting quite different lived experiences of their condition.
Closed-Loop Systems (Artificial Pancreas)
A growing number of Australians with type 1 diabetes are using closed-loop or hybrid closed-loop systems — sometimes called an "artificial pancreas." These systems connect a CGM to a compatible insulin pump, using an algorithm to automatically adjust insulin delivery based on real-time glucose readings.
Several closed-loop systems are TGA-approved and available in Australia, including the Medtronic MiniMed 780G and Tandem Control-IQ. Research has consistently shown that closed-loop systems improve time in range and reduce hypoglycaemia compared to conventional pump therapy or multiple daily injections.
Starting on a CGM: Practical Tips
Starting a CGM for the first time can feel overwhelming. Here are some practical suggestions for getting started:
- Ask your diabetes educator or GP to help set up the device and configure alerts
- Start with conservative alert thresholds and adjust over time — too many alarms can cause "alarm fatigue"
- Use the data in conversation with your healthcare team at appointments, rather than trying to interpret everything yourself
- Keep a fingerprick meter as a backup, particularly during the sensor warm-up period
- Remember that some variability is normal — aim for trends and patterns rather than reacting to every individual reading
CGM does not replace medical advice
CGM data should be reviewed and interpreted with your diabetes care team. Do not make changes to insulin doses or other medications based solely on CGM readings without guidance from your healthcare provider. In some situations — such as rapidly changing glucose or during illness — fingerprick verification may be needed before acting on a CGM reading.