Friday, 19 July 2013

Dexcom G4 vs. Medtronic Enlite: The Low Down

There are many tools in my diabetes arsenal which help me smash diabetes out of the park and continue living my life the way I want.  But there are two above all others to which I credit my current success: Continuous Glucose Monitoring (CGM) and my insulin pump, Lord Pumpington.

CGM has been around now for around a decade and gives us the tools to monitor glucose levels within the tissue beneath the skin, feeding back results around every five minutes with a lag time of between five and 15 minutes.  When I was first diagnosed in 1986, we had to pee on sticks to find out what our bloods were doing four hours ago (useful, maybe, as long as you don't have diabetes mind....).

If you are considering Continuous Glucose Monitoring, you probably have one major question rolling around your brain: which system is best for me?  There are two available in the UK; the Medtronic Enlite and the Dexcom G4.  I had the opportunity to try both systems and know that when deciding, it wasn't the gumph (actual term) spouted by the pharma companies but the experiences of others with T1D which led me to my final decision. So here it is, my breakdown of the major differences/benefits of both systems.


For this one, Medtronic win hands down.  The Enlites benefit from an automatic inserter in which the sensor sits and from which it is discharged into the skin at the touch of the button.  This means you don't even need to see the needle, let alone insert or retrieve it.  


This one is firmly in camp Dexcom.  When you insert your first sensor and have it camped out on your abdominal landscape you will think of nothing else, for a while.  Eventually however, the sensor will become as much a part of you as the watch on your wrist: you know it's there but it comfortably fits in your life, serving a purpose and earning its place on your person.  When I tried the Enlites even after five weeks and having grown used to having CGM in my life, the sensor adhesion felt 'fragile' on me - as though one good knock would see the sensor come away and £50 down the drain.  The Dexcom however feels 'bomb-proof'.  I have bashed it on walls,  scratched at it, got it caught on clothes and been through many a vigorous gym workout.  Nada. That bad boy stays put


This is the real nitty gritty and, if we're honest, a major factor if you are thinking of bringing CGM into your life.  It is a long term tool, meaning long term costs.  The options for buying include either purchasing a separate handheld unit (if you don't have a pump which can integrate CGM), or buying the kit which integrates into a pump.  I've included the actual costs on the chart below but again, the Dexcom G4 is the industry's worst-kept secret for lasting far longer than the manufacturer's recommendations, making it the much more affordable system

Insulin Pump integration

Both Dexcom and Enlite can be integrated into pumps so this one would be an even keel.  This means the results are sent wirelessly to the pump screen and are 'with you' at all times.

The Dexcom G4 can be integrated into the Animas Vibe insulin pump and the Medtronic Enlites can be integrated with the Medtronic Paradigm Veo.

The Vibe is a waterproof insulin pump which may be worth considering if you are an active water-baby.

The Paradigm Veo on the other-hand has a feature called 'low-glucose suspend', meaning if glucose levels reach a certain low-point, the pump will suspend until glucose levels rise.  Useful if you have kids or severe night-time hypoglycaemia unawareness.

For that reason, there is no winner here, just different selling point.

Low Glucose Suspend

This is perhaps the greatest feature of the Veo and certainly a consideration between the two systems.  I don't suffer severe hypos; but many do.  The Medtronic Enlite system is the only system currently on the market which has the capability to suspend the pump temporarily (up to 2 hours unless someone interacts with the pump, in which case in turns back on immediately) for the purpose of stopping a hypo from progressing further.  This means the Medtronic is the clear winner in this category

Length of wear

One of the biggest factors in making my final decision on which system I should chose was based on the diabetes community's worst-kept secret; that the Dexcom can be 'tricked' into working for far longer than the seven days it has CE approval for.  I'd heard rumours that people could get up to three weeks or so out of the new fourth generation sensors.  And it has most certainly lived up to expectations.  My shortest sensor lasted eight days; My longest, an impressive 36!  Other than that, each sensor I have used has lasted between 14 and 36 days, with the last four alone going between 22 and 36 days. I've heard of one person getting 12 days out of an Enlite sensor but personally after five weeks trial, I never managed more than 8 days.  Meaning the cost really was £50 per week.  Dexcom wins.

Overall Experience

There is a reason I wear a Dexcom, and not a Medtronic Enlite.  There are numerous reasons, in fact.  Even though I use a Paradigm Veo insulin pump (for now) and could have integrated the CGM much cheaper than by forking out for the stand alone kit, it was the accuracy, length of wear, comfort and overall experience of the Dexcom that made it the system I chose.  Everything the Enlites lacked for me, the Dexcom could offer. While there may be considerations such as the false high readings from paracetamol (personally I just switched to Ibuprofen.  Problem solved), the benefits of CGM - and more specifically, the Dexcom G4/Animas Vibe insulin pump system - mean it was a clear choice for me after having tried them both.  

And the benefits CGM has brought to my life are 100-fold:  No more overnight testing, fewer night -time hypos and continuous results driving my decisions, making working, driving, exercising and living my life, easier.  The improvements in my glucose readings are even so marked that I'm even looking forward to my next HbA1c, confident that it will be my best yet.  And for anyone's who been reading this blog a while you will know those are big words, coming from me.

Here it is, the run-down I hope you find useful:

Dexcom G4
Medtronic Enlite
£46.50 per sensor
£450 starter kit (for integrated pump.  Four sensors included)
£975 for stand alone unit (for those without integration feature on pump)
£52 per sensor
£750 for starter kit (for integrated pump.  10 Sensors included)
Unknown cost for stand alone unit.
Calibrations needed
2 per day although more results can be entered
2 per day.  No more than 4.
Length of wear (according to manufacturer’s guidance)
7 days (CE approved)
6 days (CE approved)
Actual wear by customer’s choice (not advised)
Personal experience of between eight and 36 days wear before sensors expired
Personal experience of only 8 days before sensors expired
Extremely comfortable.  Longest time worn for 36 days ith no irritation and very small entry hole.
Extremely secure when in place
Longest worn for 8 days, but aware of the sensor site at this time and reasonably irritated on removal.
Not as secure feeling when in place
Integrated into pump
Yes, only with Animas Vibe
Yes, only with Medtronic Paradigm Veo
Low Glucose suspend (safety feature to suspend pump temporarily when hypo)
Yes, when integrated with Paradigm Veo pump
Very good.  Audible, simple, easy to amend upper and lower limits
Good but less audible when pump under covers.  Somewhat over sensitive (alarms when changing very slightly).
Paracetamol use while wearing sensor?
No. It interacts with the fluid giving a false high
Yes.  No issue with fluid interaction.
20 ft, can work between rooms (with stand alone unit)
6 ft (with standalone unit)
Accuracy (MARD score – the gold standard of glucose testing. The lower the MARD, the more accurate the device is considered)


  1. Great post. Those of us in the States are anxiously awaiting both the Vibe and the Veo. Most of us using the Dex G4 love it, but we have very little info on comparing the G4 to the Enlite because the Enlite is not approved here yet. So when I see people asking about the two systems, I will send them to your post.

    1. Hi Laddie,

      Thank you for stopping by and posting. I can imagine the anticipation in the US is enormous! I'm not too familiar with what the FDA demands are exactly, but I know they are high. That is evident by the number of great products on the market that seem to struggle to make it through over there.

      The Dexcom is a superb system and I treasure it. As you say, the G4 is loved by users - I've yet to meet someone who didn't in fact.

      Feel free to share my post (and thank you, if you do). I hope it is useful in the decisions you will (hopefully) be making soon!


  2. For us the Medtronic is so accurate!!! and the low suspend far out weights any thing else that any other cgm offers.

    1. Hi Alisha

      Really glad you've had such a good experience. People tend to be in one camp or the other. For me, I know that having tried them both, the Dexcom fitted me much better.

      Keep up the great work


  3. Great information. Supposedly the dexcom folks are working with the tslim folks to integrate the two systems in the US. No word on when that will take place. Dexcom needs to develop a better inserter system as well.

    1. Oh my goodness I could not agree more about the inserter: it's like a harpoon for miniature sea-life!

      Do you always feel when inserting it that you are just one mistake away from losing it? It's never happened to me yet so guess it must be harder to do than I think, but it feels like such a pitfall-ridden process I literally hold my breath when inserting a new sensor!

    2. My greatest fear is not actually being able to insert the sensor manually due to pain. Is it really a painful experience to manually insert it vs. the inserter available?

    3. If you mean inserting the Dexcom, then I don't think it's a huge deal. I get nervous bc you do have to push it in yourself, but it's less painful than some of my pump insertions and sometimes not painful at all.

      I sometimes feel we psych ourselves out bc the first time I wore the Dex, a nurse put it in and all I felt was a pinch. I asked, Did you do it yet? So I think the pain increases with knowing that, yup, entering skin exactly this moment. :)

    4. For what it is worth I have used both long term and while it seems a bit spooky surprisingly the Dexcom is MUCH less painful. The Medtronic is like a whale harpoon and while not always, it is often painful and I too oten hold my breathhoping this will not hurt this time. Also the Medtronic Enlite sensor has a air bubble that can often fill with blood. Something which Medtronic says 'just replace the sensor', well they would considering it is another 50 - 70 euros profit for them. I have found if you jut let it sit for 20 minutes or so the blood stops bleeding and the fluid it measures (interstitial) will go back to normal.

      Another thing is that the Medtronic sensors often fail and the little sensor is like a piece of tape that slides out of the skin or comes loose and accordions up onto the skin giving sensor failure. While this does not happen often I never had it once with the Animas which remains rigid and over all I feel has a much more accurate sensor, not to mention can last twice as long (and you dont have to charge it like the Medtronic which is a pain!) Not to mention the fact that the pump itself stays charged MUCH longer than the Medtronic which they claim should be 30 days but is always out within a week and on the batteries (Energizer Industrials) that they provide.

      Another tip for those using sensors for a longer period. Dexcom tends to come loose quicker. So try putting a piece of Tegaderm Film on your skin then apply the sensor through that film. I have found the adhesive sticks better without having to use all sorts of extra tape later

  4. Hiya, just looking in to all this, my main reason being night time hypos tho improved control etc is another super reason. I read about the g4 that the cgm sensors on the meter itself only have a limited life span and in one persons case this was only 18 maths (obviously a big concern when you are probably going to be a self funder) also can you swim with the sensors on as someone else mentionned the plaster bit peeling off after being in water for longer periods of time. Last question (for now) how much and how easy is the battery replacement...finding it really hard to find anywhere with gb prices! Thank you and thank you for blogging your experiences.

    1. Hi Katherine, From what I heard the transmitter life is only guaranteed for 6 months. That said, I've been using mine 9 months with no sign of any problems. I have a friend whose went for 3 years before she updated to the G4, although I believe that is unusual. I'm not sure about the handset, but my understanding is that it should go for as long as it is looked after and charged and cared for. I know a few people who had the 7+ system and as far as I know, none needed to replace the handset.

      I'm sorry I can't be more specific - I've only been using it 9 months myself (but self-funding, so I totally get your concerns) so am going mostly on what I hear on the grapevine. The G4 has only been out around 18 months in the UK, so I'm not sure many people will have had it for long enough for the parts to fail, but it is worth asking the question.

      I am not sure about the battery replacement as it is rechargeable, but I can't see anywhere to replace a battery, so perhaps Dexcom could answer if the battery can be replaced...

      I hope this has helped (even if just a little).

    2. You speak of the meter but I think you mean the sensors? They all have a limited life no matter which brand and must be replaced. They work on an enzyme reaction and the more Hypers you have wears out the reaction, causing a shorter life, but you still can get 10 - 14 days on a Dexcom easy.

      By the way if batteries are a concern DO NOT GET the Medtronic. They have promised me that I am the only one, but I have had 3 pumps now and they all die within 4 to 7 days and they claim they should last 30, the batteries they use are expensive (Energizer Industrials) They both replace batteries free of charge if you ask, but it is still a pain that you always have to keep an extra battery at hand. I must have 50 old batteries from this past year on my desk as I write, I use them in pen lites later. In fact the meter I have now needs a new one as we speak.

      This lends the comment in another direction and people must know Animas loses all IOB or 'Insulin on board' when changing batteries! They claim this is done for safety reasons though I can not for the life of me see how such a flaw is spun to be a marketing positive. So if you forget if you bolused or not and bolus again you could get a dangerous hypo. Why they do not fix this it is beyond me. Just remember when you change the battery to make a note of how much insulin you have given yourself, as it goes to ) when you change the battery. Fortunate the Animas pump does not need batteries as often.

      I will go back to Anmas Dexcom shortly and that is one of the main reasons, longer battery life but that IOB issue really makes me angry as their CEO claimed they will do nothing about it and in fact tries to spin it like a used car salesman as a plus. We are not stupid Animas shame on you!

      The Dexcom/Animas Combo is great and battery life lasts much longer plus you do not have to charge the sensor, something you must do ever 5 or 6 days with Medtronic. If you have any problem with Dexcom transmitters they replace it as they want you buying the sensors every week. The Dexcom adhesive is rubbish I can contest but as I wrote above apply a piece of 3M Tegaderm Film to the skin first and apply the sensor through the film, then the adhesive will last for 2 weeks or more without having to resort to extra topical tape

  5. Hi Anna,

    Just wanted to say a BIG THANK YOU for posting about CGM. I found your blog and I'm now wearing my G4! 8 days so far on my stomach so fingers crossed for how long it will last. I've been waiting for years for something like the G4 and now I have it. Guess what Santa is bringing me this year, yep 4 G4 sensors....

    1. I'm so pleased! Let me know how you get on and whether you get what you hoped from it. It's like having a permanent sat nav showing you where to go before you turn the wrong way! :)

    2. For what it is worth I have used both long term and while it seems a bit spooky surprisingly the Dexcom is MUCH less painful. The Medtronic is like a whale harpoon and while not always, it is often painful and I too oten hold my breathhoping this will not hurt this time. Also the Medtronic Enlite sensor has a air bubble that can often fill with blood. Something which Medtronic says 'just replace the sensor', well they would considering it is another 50 - 70 euros profit for them. I have found if you jut let it sit for 20 minutes or so the blood stops bleeding and the fluid it measures (interstitial) will go back to normal.

      Another thing is that the Medtronic sensors often fail and the little sensor is like a piece of tape that slides out of the skin or comes loose and accordions up onto the skin giving sensor failure. While this does not happen often I never had it once with the Animas which remains rigid and over all I feel has a much more accurate sensor, not to mention can last twice as long (and you dont have to charge it like the Medtronic which is a pain!) Not to mention the fact that the pump itself stays charged MUCH longer than the Medtronic which they claim should be 30 days but is always out within a week and on the batteries (Energizer Industrials) that they provide.

  6. A really great post. I'm just beginning my search, and THIS tells me all sorts of stuff that i just can't imagine how long it would have taken me to find out, otherwise.

    1. So pleased it was helpful. Let me know if there's anything else you need to know. I'll help wherever I can.

  7. Great post Anna,

    I have tried both the enlite and the G4. Both on trial basis from the reps.
    I also much much preferred the G4.

    I haven't gone ahead with self funding as I can't quite justify the cost at present. Also I found it psychologically a challenge, that I hadn't expected.

    I asked my pump educator this week about CGM funding and was told that it's really hard and basically the only way people are getting funding is if the alternative is risk of death. I have reasonable hypo awareness so no chance at all.


    1. Hi Nikki,

      I'm guessing you're in the UK so yeah, funding is largely a 'no-go'. There are cases here and there, but on an completely individual basis. I made an application and have heard nothing.

      Was it the amount of numbers that had such a strong psychological effect on you?

  8. I am on day 12 with an Enlite sensor. There are definitely ways to trick it to think its a new sensor. This same one I have restarted 4 times. A MM rep told me the battery will last close to 30 days on one charge. The threshold suspend is awesome. In a month It has activated 3 times. Good feature for an alarm that is hard to hear under blankets. Here in the US animas and dexcom aren't integrated. I got the new system less than a month after it was released and have used Minimed/medtronic pumps since 1992. I have not dislodged the enlite sensor though I cover and retape frequesntly without removing the sensor

    1. Hey there,

      it's great that you have had such a good experience with it, and nice one for tricking it into thinking it should be going longer :) I never mastered that.

      I find it incredible that people have been pumping that long. In the UK we are veeeeery behind the times (although catching up slowly). There are still healthcare professionals here who think pumps are new! We've been fairly routinely using them for more than a decade and they really should be much more widely used than they are.

  9. I'm writing to find out if anyone else has used the Medtronics Elite sensor and had problems with the BG it reports. I'm a type 1, live in the US, and used the Medtronics Pump and companion CGM since 2009. I test about 6 times a day. Earlier this year the warranty on the pump ran out and the insurance company did an automatic upgrade. Medtronics "offered" a "special deal" for folks to get an automatic upgrade when their newest model, the 530, was released with their newest version of the CGM. I'm not so sure how good this deal has been for me.

    Since getting the upgrade a month ago, i get terrible readings from the sensor. It is generally off between 30 to 50 points and indicates my BGs are going down drastically when they aren't. Even doing extra calibrations don't help. I've taken pictures of the differences between my sensor readings (displayed on the pump) and meter (latest Bayer Contour) to show Medtronics, but the rep who called me to see how it was going, didn't want these and suggested i was using the pump/sensor incorrectly. (I've checked and it seems i'm doing it right.) Bottom line, i'm curious to know if anyone else has experienced this. I'm ready to ask for my old pump/CGM back.

    1. Hi Gezunt,

      I'm sorry that no-one has been able to help yet. Did Medtronic ever take a serious look at it. Really, if they are telling you that you are doing it wrong, it is their job to show you how to do it RIGHT! it doesn't seem they have exactly delivered here.Did they give you any advice or guidance?

      Anyway I hope your readings got better and perhaps it was a tricky set of sensors?

      Please let me know how you get on.

    2. Anna, thank you for your follow-up.

      Alas i have made no progress either with the pump or Medtronics. I've had two huge work projects that have received most of my attention. Over the weekend i did re-read the documentation Medtronics provides, and go through their on-line videos (which are quite good) to be sure i'm not missing something obvious.

      I left the transmitter in the charger all-day Sunday (and with a new battery). Monday i started another sensor from a new box, and used a completely new location (mid-thigh instead of tummy) and the resulting readings are just as bad, though the pump is "losing" the sensor more frequently. I see that others have tricked their sensors into going beyond the 6 days. I'd be happy if i could get mine to last more than 4. :-(

      Next week i'll be sending my data to Medtronics and hope to have a fruitful conversation with the techs. Will let you know what i learn.

    3. Our 11 year-old also uses the 530G. His Dexcom transmitter battery died a couple weeks back so we switched to using the Enlite sensors. The low-glucose suspend is awesome, but the Enlite is typically 15 minutes behind his actual BG. The alarm is so quiet we can't hear it in a baby monitor. When we got the replacement Dexcom transmitter we had just put in a new Elite sensor, so we ran both side-by-side for the week to compare. The Dexcom is much faster in detecting rapid BG changes and he can hear the alarm at night. I can also hear it in the baby monitor and manually suspend his pump or give him whatever treatment is necessary. The Enlite sensor fell off the first week once, lasting 4 days. The next one lasted 6 days, but we had to tape it down at day 2. The Dexcom sensor stay on our son and are accurate for 21-28 days generally (We have used the Dexcom for over a year now). We have only used 3 of the Enlite Sensors with an average of 5 days. One nice thing is, I still have a box of the Enlites, so when our son goes on special events (overnight trips or sporting events) I will have him wear both just in case the low glucose suspend becomes necessary!

    4. Hi T, I hope you don't mind but I shared your post on the Insulin Independent Facebook page too as it is really important for people to hear these kind of valuable 'real life' experiences - especially where children are involved (or those with hypo unawareness issues). I think it AWESOME you have the option of both systems, just in case. And how great for your son that if he goes away he can have that independence.

    5. My calibration experience has been the same but found that if the arrows are pointing up or down do not use it as a calibration. Also if you have eaten say 10 or 20 mins ago and calibrate now is a bad move, so you should always try to do a calibration when the value is low, say before a meal. I have found the sensors to be much more dependable if I do it this way. I have found because I am brittle and often get high #'s I am too embarrassed to admit, found that these high #'s also cause a problem with calibration. So I turn my sensor off until my level comes back down to something a bit more manageable and then ask it to find lost sensor and within 5 minutes it usually asks me calibrate. this has worked much better for me. Hope it helps

      By calibrating before a meal I find it to be much more dependable

  10. Hi there. I could not agree more about the sound volume difference in the Alerts. Enlite gives a tiny peep and the Dexcom can be set to "fire alarm". They both Vibrate well. If you have high frequency hearing loss this makes a big difference. Another small difference is the potential advantage of a separate receiver. If you have bed partner, then your partner may interested to know your glucose. He or she will have to fumble through your pajamas or under your pillow to check the 530G. If the Dexcom receiver is on the nightstand it is much easier. You get the point. thanks for a great post enlite vs dexcom. Personally, I think the MARD is a lot better for the Dexcom.

    1. 'Fire alarm' so true! I've actually never needed it on the top volume, and can even hear the low alarm through ear plugs! Totally agree about the separate receiver too. Although I have the Vibe system now I always use my receiver rather than the in-built unit as it makes life just a touch easier for me. It's great to have the in-pump system as a back-up, but the receiver is great!

  11. Hi, you state that the medtronic use needs 2 calibrations no more than 4, when it should read, 4 calibrations per day, (I routinely calibrate more than 4 times)

    1. Hi Ev,

      That came from a Medtronic rep who told me the sensor gets confused if you do too many and advised to do no more than 4. Do you find any issues calibrating regulalry?

  12. I'm in the US and have used the MiniMed pump and CGM for 6 years before trying the Dexcom G4. I was able to use both the G4 and Enlite/530G for a week together to compare. While the Enlite is certainly an improvement over the Real-Time CGM, it does not compare to the G4 in accuracy and real-time value. I did 34 meter reading over the week and the Enlite was within 0-10% of the meter 30% of the time vs 88% for G4; within 0-20% of meter 48% of the time for Enlite vs 100% for G4. The Enlite was off more than 20% of the meter reading 53% of the time vs 0% for G4. In the 3 months since I converted to the G4, I have gotten the occasional result that was outside of 20% of the meter, but it is rare.
    When you use the G4 software, you can see just how close the meter reading are to the G4 with maybe a 5 minute delay vs 15 minute for Enlite. I also found the Low Threshold Suspend feature a big disappointment because of the bad readings from the Enlite. Too bad because I was hopeful that this feature could be a game changer. Alarm fatigue is a real problem with the MiniMed product. I put the G4 receiver under the pillow at night and it always wakes me up and I know the alert is real. I'm getting 13-14 days out of each Dexcom sensor were I was only able to get 7 days from MiniMed. My only concern with Dexcom was the separate receiver and I resolved it by placing it in my back pocket with my pump. I now have much better control over lows, but still fight with some occasional highs because my insulin is just not fast enough. Hope this helps others in the US who are considering CGM. I can't imagine life with one.

  13. We started with the enlite/530g/sentry from medtronic 3 months ago (11/2014), and we have had very poor performance from the sensor. The accuracy is poor, with frequent false low alarms, a difference of more than 20% from bgs at least 40% of the time, and not infrequently differences of 50 to over 100%, poor longevity with an average use of only 3 days. Primarily because of the integration with the sentry, the pump and the threshold suspend did I decide to go with the medtronic sensor, a decision I am now regretting due to the lack of reliability and poor follow up with this poor performance by the company. In summary, we are very disappointed, and have unfortunately not found this device to be reliable, do not believe it will survive the thoughtful scrutiny it will receive, and believe it is not living up to the hype with which it was brought to market. In its current form, it is hard to understand how it received fda approval.

  14. I also use Medtronic 530G with enlite sensor and i have had constant problems like lost sensor alarms and very different sg to bg readings sometimes more than 100 numbers off. I have had to shut off my threshold suspend because it has gone off when my bg was totally normal. I am still hoping i can get it to work properly. My medtronic trainer keeps telling me it is my sensor location (i dont have much real estate to insert especially with my infusion) they tell me if your sight gets squeezed or squished it pushes the fluid away from the sensor which would lead to a low reading. Well I have tried every place other than my legs and i get the same problems. Very frustrated.....

  15. to Aaron Kimball . its not sensor location problem, otherwise it would be there with Dexcom G4 as well but it is not ! I am a physician and have used both G4 and now Enlite ( since last 3 months ) on my body. I am going back to G4 after trying Enlite enough. not worth.