Continuous glucose monitors

Also known as CGMs

Key points about continuous glucose monitors

  • A continuous glucose monitor (CGM) is a device used by people with diabetes (mate huka) to measure glucose levels every few minutes without the need for finger-pricking.
  • A CGM is useful for showing patterns in your glucose levels and alerting you if your blood glucose is getting too low.
  • From 1 October 2024 Pharmac will be funding some types of CGMs for people who meet their criteria. 
Young woman with CGM device on left arm
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A continuous glucose monitor (CGM) is a small device people with diabetes can wear to measure their glucose levels every few minutes throughout the day and night. CGMs can be programmed to sound alarms and send alerts if your glucose levels are outside your set target range, eg, if they're getting too high or too low. They can also show trends and patterns in your glucose levels for better diabetes control. Read more about how a CGM works.

What are the benefits of CGMs?

The aim of diabetes management is to keep your glucose levels in a healthy range. To do this well you need to monitor your blood glucose levels regularly. Most people use finger-prick tests with a blood glucose monitor. This gives you a one-off picture which is like looking at 1 photo or reading 1 page of a book. Because CGMs give you a continuous picture of your blood glucose levels at all times, people who use a CGM have better blood glucose control compared to using finger-prick testing alone.

  • You can see trends and patterns in your glucose levels for better diabetes control: The information collected from the CGM is usually shown as a graph. This lets you see how much time each day your blood glucose level stays within range, and records times when it goes too high or too low. This shows a full picture of how your blood glucose levels change over time and how what you eat and drink, physical activity, stress, and being sick change your results.
  • You can notice and respond to falling glucose levels quickly: Most CGMs can send you or your caregiver an alert when your glucose levels get too high or low. This makes it much easier to act before they become a problem. Remember, if your blood glucose levels go very high or very low, it's important to double-check with a finger prick test before deciding to treat, especially if your symptoms don’t match the CGM readings. See the section below, can I stop doing finger prick checks to monitor my blood glucose if I have a CGM?

From 1 October 2024 Pharmac will be funding some CGMs for people who meet certain criteria

Note: You don't have to have a CGM. There are no changes to the funding of other blood testing and insulin products. These will continue to be funded.

A CGM has 3 main parts:

  • The sensor is inserted just under your skin. The sensor is disposable and needs to be changed every few days. Some CGMs come with an applicator to make it easier to insert the sensor.
  • The transmitter which attaches to the sensor. For some CGMs the transmitter is reusable, and for other systems it's part of the disposable sensor. The transmitter sends the glucose readings to the receiver. The sensor and transmitter are held in place by an adhesive (sticky) patch.
  • The receiver then gets the blood glucose results and displays them. For some CGMs, your receiver can be a mobile phone, a tablet (eg, an iPad), or an insulin pump.

The CGM measures the glucose in the fluid surrounding your cells (interstitial fluid) every few minutes, 24 hours a day. The monitoring can easily show patterns and trends in your glucose levels.

You can set alarms on the CGM for high and low glucose levels. However, if your symptoms don't match the CGM readings it's important to double check your glucose levels by using finger-prick tests.

Blood glucose levels that go up and down a lot can be damaging for your body. Very high (hyperglycaemia) or low blood glucose levels (hypoglycaemia) can be serious.

From 1 October 2024 in Aotearoa New Zealand, Pharmac, will start funding CGMs, insulin pumps and insulin pump equipment (consumables) free of charge for people with:

  • type 1 diabetes
  • permanent neonatal diabetes (diabetes since you were born)
  • some types of “monogenic diabetes” with insulin deficiency
  • type 3c diabetes which includes insulin deficiency caused by pancreatectomy, insulin cystic fibrosis or pancreatitis
  • some atypical inherited forms of diabetes.

If you’re not sure whether this includes your type of diabetes, your doctor or diabetes specialist team will be able to help.


How can I get a funded CGM?

You will need to make an appointment with your doctor or a member of your diabetes specialist team. They will apply for funding through a Special Authority. In most cases you can get a Special Authority on the same day, but sometimes this can take a bit longer.

Once you have a Special Authority, which is valid for one year, your GP or diabetes specialist team can write prescriptions for CGMs. You will need a new prescription every 3 months.

Thereafter, every 2 years, your doctor or your specialist diabetes team will check if you’re still getting benefit from the devices and apply for a new special authority.

Read more about the funding of the following by Pharmac:


Can I get a funded CGM if I have type 2 diabetes?

CGMs for people with type 2 diabetes are not currently funded by Pharmac but they acknowledge there is emerging evidence for these to help people with type 2 diabetes. Read more about why type 2 diabetes isn't included.(external link)

CGMs can be used by themselves (standalone CGMs) or with a compatible insulin pump.


Standalone CGMs

Two standalone CGMs will be funded for people who fit the criteria. You will be able to choose either of these CGMs:

  • The Dexcom One+
  • The FreeStyle Libre 2

These CGMs work in the same way, but differ in size, look and some features. You may need advice on getting the most out of your CGM. As a guide, see standalone CGMs comparison table(external link) by Diabetes New Zealand. 

Image credit: PHARMAC, NZ

Note: A standalone CGM transmits your glucose readings to a smartphone or reader device.  If you don't have a compatible smartphone, Abbott and NZMS will supply standalone reader devices free of charge.


CGMs plus an insulin pump

An insulin pump is a small device that delivers insulin continuously under your skin. A pump can be used with a CGM to create an automatic insulin delivery (AID) system. This allows the pump to adjust the insulin dose automatically depending on readings from the CGM. Learn more about insulin pumps.

The insulin pump may also be used with an algorithm, which uses the signal from your CGM and figures out what your insulin needs are. It then adjusts the dose that your insulin pump delivers.

There are 2 funded insulin pumps in Aotearoa New Zealand. Both pumps are compatible with at least 2 types of continuous glucose monitor (CGM). If you qualify for a funded insulin pump, you can also get funded CGMs. These CGMs work in the same way, but differ in size, look and some features. You may need advice on getting the most out of your CGM. As a guide, see the CGMs intraoperable comparison table(external link) on the Diabetes New Zealand website. 

Tandem T slim insulin pump works with:

  • Dexcom G6
  • Dexcom G7

The Tandem t:slim X2 will also work with the FreeStyle Libre 3 by July 2025.

The mylife Ypso insulin pump works with:

  • Dexcom G6
  • FreeStyle Libre 3 +

Note: The number of funded CGMs per patient varies by product because they work in different ways. Find out more about how many CGMs do I get?(external link)

Image credit: PHARMAC, NZ

Note: The Tandem t:slim X2 will also work with the FreeStyle Libre 3 by July 2025.

More information

  • There are differences in how each CGM works. You may need advice on getting the most out of your CGM. As a guide, see device comparison tables(external link) of CGMs and insulin pumps by Diabetes New Zealand. 
  • For more information about the above CGMs see Dexcom CGMs(external link) and Freestyle Libres(external link).
  • You can swap between the 2 funded CGMs when you get a new prescription. You don't need a new special authority. Just ask your doctor or nurse prescriber to prescribe the other CGM.

You will usually have a training session with a diabetes nurse, a pharmacist, or with someone from the company who provides the device, to show you how to use it and how to make decisions on managing your diabetes based on the results.

Getting support

From the 1 October 2024, the helplines for each CGM will be open. If you have any technical questions, you can call:

  • NZMS, for Dexcom CGM: 0508 634 103
  • MediRay (Abbott) for FreeStyle CGM: 0800 106 10

Problems with the CGMs and insulin pumps

  • Faulty CGMs: If you're having trouble with your CGM or think it may be faulty, contact the supplier or your pharmacy for help. If it's faulty, the suppliers will provide you a replacement free of charge. Any CGMs provided to replace faulty ones would not count towards your annual limit.
  • Broken or lost CGMs: There's a limit on the total number of CGMs you can have each year that takes this into account. If you’ve used more than the limit, you may need to pay for more CGMs. Check with your healthcare provider how many CGMs you can get.
  • Faulty insulin pumps: If the insulin pump is faulty, or an issue develops, you will need to contact the supplier.
  • Broken or lost insulin pumps: If your insulin pump is broken or lost, talk to the supplier about your options. But be aware that you may need to pay for a replacement. Pharmac funds 1 new insulin pump every 4 years which is the warranty period on insulin pumps. You may be able to claim a broken or lost insulin pump on your household insurance.

Finger prick readings are still very important to manage your diabetes. Using a CGM means you’ll need to do them much less often.

Finger prick tests may be needed to help calibrate the CGM (check it's reading accurately) and at times when blood glucose levels are changing quickly (eg, if you're dehydrated, after doing extreme physical activity, or after certain foods or medicines).

You should still check your blood glucose level using a finger prick test when you are sick, and if:

  • You have symptoms of low blood glucose but your CGM reads above 4 mmol/L: If the blood glucose level on your finger prick test is below 4 mmol/L, you're having a hypo and must treat it immediately. Read more about how to treat hypoglycaemia (low blood glucose).
  • Your CGM reads below 4 mmol/L but you don't have symptoms of low blood glucose: Only treat yourself for a hypo if your blood glucose level on your finger prick test is below 4 mmol/L. 

Note: Finger prick readings measure the amount of glucose in your blood. CGM measures the amount of glucose in the fluid surrounding your cells which may be 2 to 10 minutes behind your blood glucose levels. It’s normal for these results to be a bit different, what's important is the pattern of changes in your readings.

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Credits: Healthify editorial team. Healthify is brought to you by Health Navigator Charitable Trust.

Reviewed by: Angela Lambie, Pharmacist, Auckland

Last reviewed: