Unboxing and applying the six CGMs

To start with, let’s make it clear on the source of each of these devices:

Provided by the manufacturer for free:

  • Dexcom ONE
  • Medtrum Nano

Purchased by me:

  • Dexcom G6
  • Glucomen Day
  • GlucoRX Aidex
  • Freestyle Libre2

Could be obtained freely on prescription now or soon:

  • Dexcom ONE
  • Glucomen Day
  • GlucoRX Aidex
  • Freestyle Libre2

I was going to start off by documenting details of what was in each of the boxes, but with so many, it quickly became clear that there’s not a lot of benefit to this.

Essentially, there are sensors and transmitters arranged across multiple boxes, with varying levels of instruction manual or leaflet in each.

It’s worth noting at this point that not all of the systems available on the prescription tariff will support insulin dosing. The GlucoRX Aidex (the cheapest) is not approved for this use. The others are. This means that if a CCG pushes users towards the Aidex, they will need to continue to supply enough test strips to support mealtime treatment decisions. At my estimate, that would be a minimum of 4 per day, or two boxes of 50 strips per month. Given that requirement, while the Aidex is the cheapest on it’s own, the monthly cost needs to be increased by ~£40 for treatment decisions, making it far more expensive than the alternatives.

As part of the unboxing, I was looking out details of whether a system is indicated for dosing insulin, and I’ll be honest here, that’s not always that clear. Not all the sensor or transmitter packages contain useful leaflets or booklets, and a fair number are written in tiny writing. Most of the apps contain instructions regarding safety, but they differ in how they approach discussion of use of devices for treatment.

What’s clear is there’s room for improvement in this case. It should be made clear whether a device is approved for treatment decisions or otherwise, and there should be a consistent approach to delivering that message that is comparable across all manufacturers. That isn’t really the case right now, as the two images below illustrate.

These are taken from the Glucomen Day and Dexcom G6 manuals. The Glucomen manual buries the treatment decisions section at chapter 14 and contains less than a page of information. The Dexcom manual puts this at chapter 5, contains the best part of six pages of information and also contains examples for a user to work through to help understand how to use the system better.

These are clearly quite significant differences in approach.

Pre-attachment – a checklist

Before attaching any of the sensors, it’s worth running through the apps and manuals to find out what info you need to supply prior to attachment, either of the sensor to you or the transmitter to the sensor. The apps make this pretty clear as you work through them, but it would be possible to mess up on a couple, given the connection process. There’s also the requirement to charge some of the transmitters before you can apply them. Again, this slows you down and is a step that you don’t want to miss.

Once all the apps are downloaded and the pre-application tasks completed, then you’re off. Time for installation!

Attaching the transmitters

The below video shows how each is attached. Due to its mostly reusable nature, the Glucomen is by far the most complex to apply, and I suspect if you were partially sighted, the set-up of the installer would be a larger challenge than plugging the transmitter into an attached sensor, or applying an all in one, such as the Freestyle Libre2.

As an adult male, the least comfort of these to apply was the Aidex, as it requires a dual action of pushing down and then hitting a button, which is pretty fiddly.

I wouldn’t say that any of them was painful to apply though.

Attaching transmitters was another point. The Dexcom transmitters are designed in such a way that it’s very easy to align them on to the sensor. The Glucomen is already attached when you apply it. And then you have the Medtrum and Aidex. As the transmitters are symmetrical in shape, you have to check to make sure you’re aligning the contact point on each transmitter with the sensor. More of a challenge if you have eyesight issues.

Once the transmitters are connected, there are different steps to go through, depending on the system.

On the Dexcom devices, you’ve already set up the sensor and transmitter ID, so you have to start the sensor in the app.

On the Aidex, at first connection, you have to pair the transmitter, which you’ve already attached, so you better have noted the serial number. It then asks if this is a new sensor, and warms up.

The Glucomen and Medtrum both detect the sensor connection, having already been given the transmitter details, and start to warm up.

And of course, you have to scan the Libre. And then you wait for your sensor to warm up, between one and two hours, dependent on Sensor.

The waste…

The least waste is a tie between the Medtrum and Glucomen devices. The most easily disposed of is clearly the Glucomen, as there is no needle to dispose of. It uses the sensor itself.

The largest amount of waste is a toss up between Aidex and Dexcom.

Is any of it recyclable? The plastics don’t feel like the types that are, but if any of the manufacturers would like to correct that, it would be good to hear from them.

Additional sticky patches

As can be seen in the two pictures above, it’s possible to get manufacturer supplied overlay patches to provide better adhesion on all but the Libre. They come in the box with everything except Dexcom, where a request is needed to the service centre.

In theory, these should ensure the 14 or 10 life of each of these is fulfilled. That’s something to wait and see on.

Closing thoughts on the application and start up process

They’re all relatively simple to attach, although the nature of the Glucomen perhaps makes it the most complex, while the Libre2 is the simplest.

None of them particularly hurt.

If you’re familiar with using one CGM, changing to another and getting started won’t be too big a challenge for anyone as they all provide variations on the same user experience when going through this process.

What’s clear from getting the packages, opening them up and applying them is that if there are rules or standards relating to what you get in a CGM package, they aren’t followed, with different systems taking different approaches. The application devices and processes are restricted by patents, but the information within a package, and documentation relating to treatment should be consistent across all.


  1. Are you going to check their accuracy against fingerpricks?
    I’m using the medtrum as my main sensor currently, but I did just trial the Libre3 and used the Dexcom G6 as my primary for a long time. I found the G6 the most accurate, the Medtrum is occasionally buggy and the Libre3 app is appalling.

  2. Great to see this type of proper comparison. Some call for comparison with fingerprick – but how do you standardise fingerpricks? Many people use BGM error figures but completely ignore the errors of different strips : and only take a Single fingerprick. I am not asking you to submit to 6 consecutive fingerpricks with 6 strips, repeated for a number of different BGM but that would be the Only true comparison ….

    • Or you can use the same meter and set of strips that the DTS has identified as the system with the lowest variance. Which is the Contour Next system, and what I use for these tests.

      Let’s be honest, what we care about is howbfarbitbis at a point in time from the alternative way of choosing how much to dose, and a single fingerpricknis generally how we’d do that.

  3. I know how much the fingerpricks can become less than desirable to do everyday. The patches are a great alternative. Are you tired of the fingerpricks or do they not bother you at all?

    • I’ve been using factory calibrated CGM for a number of years, so rarely fingerprick. The 8 a day for these tests does become a bit cumbersome though.

Leave a Reply

Your email address will not be published.