Enhanced enlite sensors vs Dexcom

I know Dexcom has generally got the cake for accuracy in the CGM market, but now Enlite v2 or 'Enhanced Enlite' are available (in Canada at least maybe for a year in Europe) I'm curious to know how they compare. I've heard that for sure the new Enlite are much better than the old Enlite sensors.. but how close to Dexcom G4?


The official website makes some claims:
- 80% smaller in volume

and says
"2 MiniMed 640G with Enlite has a MARD of 13.6% [MiniMed 640G User Guide] when calibrated 3-4 times daily."

though isn't clear if that's the new or old Enlite.. assume new? Except that this page makes that same statement and appears to be talking about the original Enlite sensor (since its comparing it to SofSensor)

That anecdotal info from the cwd forum sounds pretty good but.. *shrug* It is extremely difficult to be sure which Enlite is being talked about in most articles/press releases. Since the first Enlite is called the 'new' Enlite and the second one has the same name but is sometimes called 'enhanced'

I am at my pump renewal period getting ready to be locked in for another 5 years and it seems like most things are pulling me toward Medtronic (used to dealing w them, very good customer service, nice interface, I have a loaner pump from them and might be screwed for a bit if I decide to jump ship) BUT the accuracy of CGMS (not currently using a CGMS tho) and potential for better data interoperability w Dexcom are the sticking points

The Dexcom G4 sensor with the 505 firmware update claims a MARD (mean absolute relative distance) of 9%. Since you like the Medtronic pumps, why not consider a new Medtronic pump and Dexcom CGM? Does Medtronic make a current pump without the CGM capability?

Dexcom is more accurate than Medtronic and its sensors last longer. I usually get 14 days out of a sensor. Dexcom's upgrade of firmware recently allowed all current users the ability to refresh their system. I think that Dexcom will continue to iterate more quickly than Medtronic. Their G5 system will be able to catch a signal from the Dex transmitter and display directly to an app on the iPhone and I assume the Apple Watch.

Dexcom appears more nimble at this point. I'd rather bet on them to feature the latest improvements more quickly than Medtronic.

I am at my pump renewal period getting ready to be locked in for another 5 years

Four years, not five. Or at least four years is the length of the warranty on the Medtronic 723 pump I got in March of 2013 and of the 722 I got back in 2008. I remember it used to be five years. I am not sure when it was reduced.

If all you care about is accuracy, then yes, you need to consider Dexcom. However, if you can live with "usually good" accuracy & tolerate the more technically tedious nature of Medtronic's CGM, then you might want to look at the pros & cons more closely.

I agree that Dexcom appears to be more nimble at this point. Medtronic's idea of releasing a software update to tweak its sensor algorithms is to sell you a new model pump, not let you download & install the update. But Medtronic also is ... or at least should be ... motivated to continue to improve their sensor accuracy if they want to continue to use the phrase "artificial pancreas" without folks rolling in laughter when they do.

But frankly, I'm not sure what your options might be with Medtronic at this point in time. At least being in Canada you've got a shot at getting the 640G sometime before the end of 2016. I have no idea how likely that might be though. The Medtronic Diabetes Canada website is still currently showing the Veo as their "most recent" pump.

My personal opinion is that upgrading to the Veo is probably not that much of an upgrade. If Medtronic offered to upgrade you from the Veo to 640G for "close to free" when the 640G comes your way, then it would make sense. But I doubt they would do that.

FWIW, the enhanced Enlites, while definitely an improvement, are not a drastic change. The fact that Medtronic apparently uses the same product code for both the earlier & the newer "enhanced" Enlites is IMO an indication of how minor the changes must be.


Duh. In hindsight maybe the warranty still is five years in Canada and only reduced to four years in the US. If that's the case I apologize for my myopic assumption.


I am always sort of drawn to the Dexcom since everyone says it's so much better. I'm totally lazy about changing, although I went so far as to sign up for an account with Dexcom, I haven't bothered following up on it, other than getting automatic sales emails. I've done very well with the Medtronics. I know bunches of people with Dexs who, at dinners, etc. will test and discover their Dexs to be "off" by margins of error similar to what I occasionally see with my Medtronic Enlites (I presume V1?) which makes me think that the advantage is not all it's cracked up to be. I have to figure out a way to try them side by side however that seems as if it will require some sort of declaration that I want a Dexcom which I'm sure will be a chore with insurance, particularly as I'd be hesitant to do it without some assurance of "backsies".

I'm not a huge fan of the Threshold Suspend feature as I am a control freak and have seen that killing basal like that tends to blast my BG through the roof. I haven't had a situation I haven't been able to stay on top of my BG but I could see that it could be a helpful safety device. I think the Medtronic pumps are very solid and attribute some of the success I've had with it to accurate, precise delivery of insulin. I've also found the sensors to be very accurate when things are stable.

I also met with the TSlim sales guy, a friend of mine had talked to him and 3 of us met with him. The ther two bought one. It's a very impressive toy but again, not worth it to make the change. Like the Animas Vibe, the Tslim is also reputed to have a Dexcom version close to launch but it's also using the older Dexcom model rather than the latest edition? Maybe that's a rumor but the way the FDA rolls seems to interfere with patients getting our hands on the statest of the art integrated pumps.

I started with the Medtronic Enlite CGM sensors in late January (with a new 522 pump) and have been hugely disappointed in the lack of accuracy. I only wish the MARDs quoted above were what I experienced. I saw more like 20, 30, 50% off blood glucose readings, or worse. This is with multiple sensor rounds, varied injection sites, etc. Accuracy is so bad that, IMHO, it is worse than useless. No rhyme or reason to the direction of the error, which is awful. The number of false alerts caused by this inaccuracy was annoying at best, and misleading at worst. They say over and over, do not rely on the CGM for treatment decisions, but what is the point then? I am pretty sure I will discontinue use of the CGM.

HI everyone, I just joined so that I could join this discussion. Ken, I had nothing but problems with the MM Soft Sensors--so much so that I got a refund after trying numerous sensors over the course of the 30 day trial period. That was more than 3 years ago, IIRC. At least 2, for sure. I used to refer to it as a "random number generator". Spent hours on the phone with tech support and MM even had a local rep come out to see if she could spot anything wrong with my sensor placement.

Fast forward to Sep 2014 when my wife switched from the Soft Sensors to the Enlites. She let me try it for about a week and it worked surprising well. So well in fact that I ordered a 530G and Enlite myself in December. Sometimes the sensors don't work well or they work well for a few days and then have very low ISIG's. MM has replaced at least 5 of them for me, but it takes a lot of my time on the phone to deal with getting replacements.

Now the good news. I've had some sensors work so well that I am "afraid" to calibrate them at each 12 hour interval. The readings from a good sensor will be within a couple of points from the Contour meter or it's a bit off (when my bg's are moving) but trending in the right direction, and given another 15 minutes, it will read about the same as the meter.

I've had several sensors work well for 8-9 days, and today I am almost up to day 11 with ISIG's running nicely high. This sensor is the first one I have place close to my side, rather than closer to my centerline. Many sensors I've placed roughly 3.5" from my belly button. The current sensor is about 7+ inches away from my BB. I tried that location because the fat feels softer in that area so I thought that might help with interstitial fluid issues.

Whenever I lie down, the ISIGS MIGHT drop, so I never calibrate for at least an hour upon rising. TO do so earlier would set up the system to soon report erroneously high glucose numbers because upon rising, the ISIGS come up on their own. MM knows that issue and agrees with not calibrating right after rising. If I lay on a sensor the ISIG's will drop dramatically but when I sleep on my back, I find that wake-up glucose numbers to be pretty close to correct.

By carefully selecting the HIGH and LOW alert values, and the mg/dl rise/fall rates, I've gotten quite a lot of useful alerts that help me avoid getting high or low; especially high which I hate because when I do my PN acts up almost immediately.


Sorry, I made a mistake on the day my current sensor is on. I am starting day 13; not day 11. LOL! Guess I can't add 6 and 6 properly...

If you are having problems with the Enlite the first thing I would suggest is to watch the insertion training videos from Medtronic Australasia (ANZ). While not a panacea I think they are vastly better than what Medtronic US offers. The Medtronic ANZ videos will actually describe what NOT to do and point out some common mistakes.

Here are the links.

My unproven speculation is that the main reason for sensor inaccuracy may be due to not securing the sensor properly with the overtape. If the sensor probe can be jerked around then the sensor readings are going to be jerked around as well.

I suppose it's also possible in some cases the sensor assembly is being damaged when inserted. I originally did not think this was a reasonable possibility. But then I saw a pair of YouTube videos from a women who started out hating the Enlite. She then posted a "I love it" follow-up video later. The things she claimed she was doing during insertion before she "saw the light" I never would have believed anyone would do. But then what the heck to I know ...


I started with the Medtronic Enlite CGM sensors in late January (with a new 522 pump) and have been hugely disappointed in the lack of accuracy.

Wait a minute. It just registered with me that you wrote about starting with a "new" 522 pump in January? Of 2015?

In the US, the Medtronic 522/722 pump was introduced sometime in 2006. It was then replace sometime in 2010 by the 523/723. The pump Medtronic currently sells in the us is the 530G which I think was introduced in October/November of 2013.

So ... typo?


I'm using another excellent sensor that is now on day 9, 11 hours and going strong. what a difference the right body location makes for good ISIG values that persist well past the 6 day "limit". Many times the sensor reading exactly matches my meter readings or is within 10 points. coming from me, the guy who had to return for refund, the Soft Sensor system, AND nearly returned the Enlites sensor back in January, that's quite a turn around.

About picking an Enlite insertion site ... I have several alternate insertion locations with lots of adipose potential which I can't use unless I could find someone to assist me. #NeverGonnaHappen

One spot I have always wondered about is my (upper) buttocks. I stopped wondering about that after I watched this “Enlite Sensor tips” video blog entry which includes a demonstration of inserting an Enlite in the upper buttock area.

At around time 3:33 you can watch as the presenter applies the overtape. There is simply no way I currently have the flexibility to get both of my hands in that area of my body the way he does. <sigh />

For those out there who don't want to watch the video but might be interested in the 7 tips, I copied my paraphrasing of the suggestions in the video below.

  1. Insert with the sensor MiniLink transmitter vertical (portrait) NOT horizontal (landscape) and in an area less prone to twisting and turning.

  2. Hold the inserter GENTLY pressed against the skin while inserting. Pressing too hard can cause kinked sensor probes and other problems.

  3. Try products such as Skin Tac (applied after inserting) to help prevent the sensor probe from being moved or pulled out.

  4. Connect the Minilink transmitter ASAP. Don't wait longer than 5 to 10 minutes to connect the transmitter as this can allow hydrogen peroxide to build up which could degrade the sensor's performance.

    Note: this is the exact opposite of the practice many folks used to practice to get better results with the older Medtronic Sof-sensor (aka Harpoon) sensors. Allowing an Enlite to "marinate" before connecting the transmitter could have the opposite effect from what is hoped for. It could make things worse by damaging the sensor.

  5. Gently pull the security tape (overtape) over the sensor base to pin it in place and prevent it from shifting.

    Note: Also mentioned in the vid was to never pull the tape tab which secures the transmitter too tight. If you do it can lift the transmitter up off your skin resulting in a V-shaped or rocker effect that can pry the sensor base & probe loose.

  6. After attaching the Minilink, use additional tape to secure it and prevent clothing from snagging on it and jostling it.

  7. DON’T WAIT TO CALIBRATE. Calibrate as soon as possible after you receive the meter BG.

FWIW, -iJohn

You touched on quite a few points my trainer mentioned.

She told me to try Mastisol, which I bought, but i dont really like it as much as Skin Prep (not to be confused with IV Prep). Skin Prep applied, and dried for just a few seconds (about 10-15) gives me better adhesion of dressings such as IV3000 than an application of Mastisol. I've only tried Skin Tac once and didn't find it all that great at preventing dressings from coming off in hot weather/sweating.

I have a sore spot from the corner of the transmitter over-tape. It's hurt so bad I removed the top dressing and placed a bit of gauze at that corner to keep my skin from becoming further inflamed. This one sensor installation is the only time I've had this issue with the xmitter tape.

I always calibrate as soon as it says I can.

I do ok without extra tape on the Enlites. I think the stock tape gear works pretty well. It's interesting about not letting the sensor "marinate" (LOL...) as I always wait until the transmitter is recharged, which ends up being 15+ minutes but have gotten decent results out of it.

This week, I've had a sort of confluence of events, moderately big bike ride day (28 miles, c. 17 mph, lots of wind one way...) was yesterday, day 7 of the xmitter charge and it was still reading solidly so I rode it out and then the battery died this AM so, instead of pulling it and sticking a new one in, I pulled the xmitter off and recharged it and it seems to be working as expected, which is interesting to me!

Neither my wife or i can get more than 7-8 days from a battery charge, so from now on I will always recharge it when I restart a sensor at the end of 6 days. right now i am at day 11, 10 hours. ISIG is 38. I have gotten "lost sensor" when the battery is apparently low. too bad the pump never shows the battery as "weak"

It's interesting about not letting the sensor "marinate" (LOL...) as I always wait until the transmitter is recharged, which ends up being 15+ minutes but have gotten decent results out of it.

As with any "advice" ostensibly from Medtronic, there is not enough background detail to give insight into how much trouble you might bump up against if you don't follow it.

I assumed that this caveat was intended much more for those folks who would insert their Sof-sensor in the evening sometime before going to bed but would intentionally not connect the MiniLink transmitter until they got up the next morning. There are a lot of pre-Enlite posts from folks who swore that they got the best, most consistent results from a Sof-sensor by following that protocol.

My guess is while you could get away with waiting overnight to connect to a Harpoon, those sensors were also just not as sensitive (?) to glucose as the chemistry of an Enlite appears to be. In my experience the ISIGs for a Harpoon were always around 1/2 (or less) of what I expect to see from an Enlite for the same glucose level.

To put it another way, don't assume that the same tweaks you used with the Sof-sensor are also apropos for an Enlite. Enlite has it's own set of quirky quirk quirks. ;-)

Out of curiousity, have you ever looked at the ISIG value reported shortly after your pump has established a connection with the transmitter? I'm not sure if it means anything, but I'm used to seeing ISIGs in the 100s at that point. They then quickly drop to the levels I am more used to seeing.

Possibly part of what happens during the "warm-up" process is a bleeding off of this "excess" (?) current to allow the sensor to reach some degree of homeostasis?


I do ok without extra tape on the Enlites. I think the stock tape gear works pretty well.

What the person who did the vlog was referring to is what is described as "Tip 2: Additional Tape: Apply over the sensor and transmitter for added security" in this Medtronic pub (PDF): Additional Tape Tips.

The additional taping options, which use only the overtape which comes with the Enlites, are also demonstrated in this "Additional Taping Methods" short YouTube video from Medtronic ANZ.

I always do something to secure the transmitter beyond just folding that short tab over the back of it. It's just not worth it to me to take the chance the transmitter might snag while dressing or undressing. But of course, YMMV.