Revisiting the Medtronic Enlite CGM Sensor

A couple months ago, I wrote about my frustration with the Medtronic Enlite CGM sensor. It was the follow up to my first impressions post, which was actually my view four months in. Those dispatches, along with the one about what I’ve learned while using the Sof-Sensor are among the most popular articles here. (At least if you look at the number of comments.)

When I last wrote, I was quite disappointed with the accuracy of the readings I was seeing and decided to call my endo to get a new prescription for Sof-sensor sensors. (Man, “Sof-sensor sensor” feels awkwardly “corporate” to write . . . like writing “MiniMed® 530G with Enlite®.” But I digress™.) Anyway, I called to start the process of getting a new prescription and then went on vacation to do RAGBRAI. [1]

And do you know happened? Of course, you do.

The accuracy got better. For the most part, it’s been believable enough that I forgot about going back to the Sof-sensor. Two months later, I still have wonky sensors about 10-15% of the time, some incorrect readings during exercise, and the occasional buyer’s regret with the whole Minimed line—especially after talking with Céline in depth about her waterproof Animas Vibe with integrated Dexcom CGM—but the results are good enough that I feel much better about the 530G and Enlite.

What changed? What’s different now?

At first I thought it was because I wasn’t running or swimming as much during those two weeks. In fact, I only swam twice during that fortnight. And when I got home from vacation, the pool was closed, so I swam in the lake a couple extra times per week. Perhaps there was something about the chlorinated water or the twisting of my body that was throwing off the interstitial glucose (ISIG) values. Perhaps the sensors didn’t like being in the water for 60-80 minutes. Perhaps being under my wetsuit prevented the tape from getting loose, which is the death knell for these little guys in my experience.

But no. I’ve been back at the pool for a few weeks now, and the sensor accuracy is just as good as when I was on vacation (which is to say, pretty good).

Another thought I had on vacation is that my hydration is better or more consistent, but I’ve decided that’s not the case.

The two thoughts that haven’t yet been disproved are these:

  1. I’m inserting the sensor in almost exactly the same place each time. For the last two months I’ve been placing the sensor within a 2-by-2 inch patch of real estate on my left hip just above my belt line. Someone will probably tell me this is a bad idea, but there’s something magical about this location. There isn’t much scar tissue there; it’s not near “gusher” territory; that place has just the right amount of flab; I don’t tend to sleep on it; and it doesn’t seem to move very much along with the rest of me when I twist, sit, etc. It will be a shame if I’m forever bound to this one spot, but whatever works. [2]
  2. I’ve stopped using extra tape, except as a last resort. I used to cover Sof-sensor sites with Tegaderm™. That locked them in good and tight and seemed to be just what that sensor needed. The Enlite sensor appears to be much more of a free spirit. If I put any extra tape on it to keep it from moving around, I find that the sensor filament gets kinked more easily. (Remember: “kinky = bad” when it comes to sensors.) For the most part, the Enlite tape and overtape stay attached well, although it took me a while to feel confident that it wasn’t just going to pop out when I went swimming.

I also calibrate less now than before. This is partly because the readings are closer to my actual blood sugar. Plus, calibration doesn’t have any impact on the ISIG readings from the sensor. So I’m inclined not to think this is part of the solution, even if it is good practice.

My problems with the Enlite were real but not widely shared. At the JDRF ride in Tahoe a few other Minimed users I talked with rarely had problems with bad readings. One of them even cuts IV-3000 to add extra staying power to her sensor. She also talked about getting 3-4 weeks of good readings from them. (Lately I’ve been getting 10-14 days from the good ones.) Whatever works, right?

I’m just glad that things are working.

How about you? Do you use the Enlite sensor? How is it working for you? I’d love to hear your experiences.

1 — My local Medtronic trainer/rep called while I was on vacation to see how she could help me get the sensors working better. This is really great, and I should probably call her back. Now that everything is working pretty well, it keeps falling off my list of things to do. [Back . . .]

2 — One of the JDRF coaches at Tahoe was talking about how she places her Enlite sensors in the same place each time, too. I happened to walk into that conversation at the exact moment she said, “I always stick it in my butt.” Good times with diabetes. Good times. [Back . . .]

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3 Responses to Revisiting the Medtronic Enlite CGM Sensor

  1. scully says:

    I’m happy to hear that things have made a turn for the better. I hope they stay that way and you keep using whatever magic you have to maintain that. I always found the cgm to be so strange because it seemed to work more on the rotation of the earth than it did on trial and error.
    I’m relieved to read this. :)

  2. Marcus says:

    Though I ultimately gave up on Medtronic and happily went back to the Dex, one of the best pieces of advice I ever got is the one you mention about calibrating less, even when it’s horrible. That makes no sense to me, but I always got way better accuracy when calibrating only 2-3 times per day.

  3. Erica says:

    Glad to hear you are liking the CGM with Medtronic more now. One thing I have found as well as my Type 1 Diabetic Endocrynologist is that if you put the sensor in your arm, if you’re stand it would sit facing ahead, beside your armpit- the readings are slightly more accurate than on the waistline. I know you swim frequently so I’m not sure if you’d like that location but it might be worth a try. Sort of directly above your elbow, so it’s not really touching if you lay on your side while sleeping for example.


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