Monday 16 May 2011

Second time lucky - re-visiting CGM

It is no secret that I wasn't the biggest fan of CGM (Continuous Glucose Monitoring) when I first gave it a try. Don't get me wrong - the theory behind CGM is brilliant - pure genius in fact. And I hope that the person or team of people who came up with it are now being fed fresh fruit and fanned with a giant feather Cleopatra style on a beach somewhere, having retired at the age of 32. The idea, is great. But unfortunately when I tried one (the Medtronic Real-Time system) it left a fair deal to be desired. While the idea of information itself is invaluable if correct, there are several boxes CGM needs to tick in order for it to match up to the gold dust label it has acquired over the years.

For me, if I am to find a way to pay for CGM, there a 4 simple things it needs to be:

  • Reliable

  • Affordable

  • Comfortable

  • Easy

When I last tried CGM using Medtronic's Sofsensor, I found that the accuracy of the blood vs sensor readings were so wildly different that I reached new levels of blood testing madness, because I simply didn't know who or what to trust. I think on the first day I clocked up something ridiculous like 25 blood tests. If the sensor was to be believed, I was going from the brink of coma to surfing the teens several times a day. Even at best it was usually always 3mmol or so out. I also found that it got so 'confused' during periods of hypos, that I would end up turning the alarms off and letting it just get on with its melt down quietly. In fact CGM should always be used to look at trends instead of precise readings, but I experienced several episodes of moving in different directions entirely. Not particularly re-assuring for something desinged only to re-assure!

I also found that contrary to what people had claimed about wearing it for up to 21 days (!), after 6 days I would have paid Medtronic to take it back. I wanted to wear them longer because this would reduce the cost drastically. In fact I am fairly confident you could support a mild smack habit over affording CGM, if you only wear each sensor for 6 days. I wanted to wear it longer, but truth be told could have ripped it out sensor first given half the chance, because it caused so much irritation and discomfort. On top of all that the sensor left me with such sore, red and irritated blotches that it would have taken some serious work to convince people I wasn't harbouring some sort of infections disease - just what you want in bikini season!

So when Medtronic invited me to try out their new system after releasing the new 'Enlite' sensor and making some pretty big claims about the improvements, including a 69% smaller sensor, 98% of hypos detected (out-doing market leader Dexcom 7+) and being much more comfortable, I was rather excited at the prospect of giving it a go. So this weekend I was invited up to the Medtronic office in Watford (like going back to the Mother ship for some strange slightly star-struck reason) to get fitted with one of these 'magical' new sensors.

Well so far I have to say I am pretty impressed. Insertion (with the new automatic inserter) was easier and quicker than with the somewhat clumsy and fiddly predecessor. And to prove this we were encouraged to use the sensor in an area we hadn't used before. In my case, I used my 'luurrve' handles (sounds much less gross if said in an inappropriately sexual way, don't you think?!) and actually attached it without even seeing what I was doing (although with a little help from the Medtronic team).

Comfort wise, I have been wearing it over 2 days and honestly haven't really noticed it. Provided it is placed higher than your waistband (which common sense said it should be anyway) there is no rubbing to worry about. On top of this, Medtronic have added some extra adhesive material, meaning you don't need the sticky and extremely un-sexy medical Tegaderm that we were encouraged to use before (and left you looking like some sort of experiment). There is no 'flopping about' of the transmitter on the skin which bothered me so last time, and generally it feels very secure.

As for accuracy, although Medtronic only appear to have made claims about the accuracy of the hypo detection, it is actually the accuracy the rest of the time I have been impressed with. While I have still done several tests in the last two days, I have so far not proven the sensor wrong yet and there have been many times when the sensor and blood glucose have matched almost exactly (in fact 10 minutes ago my BG said 4.9 and then sensor now says 4.8.......). Bearing in mind there is a 15 minute difference between blood glucose and interstitial fluid glucose (which is what the sensor is reading), I call that pretty precise.

The biggest test for me knowing now how much the accuracy has improved, will be the longevity of wear. Unfortunately one thing Medtronic have not been able to achieve, is a lowering of the cost. In fact I believe the cost is marginally higher than in comparison to their old sensors. For the old Sofsensors with their sketchy accuracy and their trigger happy warning arrows, it just wasn't worth it. The new Enlite sensors however are vastly improved and if they can remain this comfortable even for 10 days rather than 6, this could just be something which can become manageable.

I will definitely keep you posted about amount of time I can wear it for and how reliable they remain and will let you know what my overall feeling is after the trial finishes. But for the time being at least, this previous sceptic is feeling positive.


  1. hi - would be great to hear an update - thanks

  2. Hi Anna
    I came across your blog looking for info on CGM - my 3 year old little girl was diagnosed with type 1 diabetes 2 weeks ago and I'm looking for as much info as possible on the condition, pumps etc etc. We qualify for an NHS funded pump because of her age and I'm looking to possibly supplement this with CGM. Do you know how much the new sensor costs? My diabetic nurse said it isn't funded and costs around £52 per 6 days.... I'm desperate for as much info as possible at the moment.... thank you, marisa

  3. Hi Marisa,

    Your nurse is right that for the Medtronic Enlite sensors they work out as around £52 per sensor if you buy ten at a time. Clearly that is a huge cost! Have you looked into NHS funding for CGM? Some people have managed to get funding, there is a blog link here ( for a lady who managed. My initial advice would be to look at getting on the pump initially to see how much of an effect this has. The difference it made to me was enormous and it could that this alone will give you the increased control you need. It is also a lot to take on in one hit, so perhaps getting to grips with the pump first and going from there may be an idea. Happy to discuss via email but need to set one up that I don't put on a public forum!


  4. Hi Adam,

    I have now added labels as the blogs were a bit hard to follow, but hopefully this blog ( gives an idea of how I got on

    Are you considering CGM yourself?


  5. hi - yes indeed - got the veo and cgm a month ago - all going very well indeed and i am glad to have made the leap to the pump and cgm - it is a bit expensive but i can get about two weeks out of each sensor and that helps a bit - keep blogging - great read

  6. That's great news! So glad it is going well. I am a big fan of the Veo particularly with CGM.

    Good luck and keep me posted!