Earlier this year I pre-ordered a Blucon Nightrider from Ambrosia Systems (https://www.ambrosiasys.com/). This is the reusable device that sits on top of the freestyle libre. Well, a few months ago I started on a minimed 630g with Enlite sensors and forgot about the Blucon until it arrived a few weeks ago. I happened to come across a couple of unused Freestyle Libre sensors during my seasonal cleaning so I thought I would give the system a try.
The blucon itself is about as thick as a pen and takes a standard watch battery:
It needs something to hold it over the sensor so I just stuck a grifgrip over it. It kind of bulges out when added to the thickness of the sensor.
The nightrider is not waterproof but with the grifgrip I’ve showered with it and it seems to work fine. I don’t have it covered well enough to go swimming with it.
There is an app to download and I have an Android phone so I can’t comment on the iOS version. After starting the app you have to pair the phone and the device. To reset the blucon device and make it pair you have to get a pin and push into the tiny hole on the top. A light blinks red indicating it was pushed. Then you tell the app to scan for a device. This tripped me up a little because it found my device but then got stuck waiting for data. There wasn’t a notification it successfully paired and it went straight into reading from the sensor, which wasn’t attached at this point.
I activated the sensor with the Libre reader and then the Blucon. I was a little surprised the blucon started getting readings right away while the reader made me wait for the 1 hour warmup period. So that was the first giveaway that the Blucon is reading raw numbers and does its own interpolation/analysis of interstitial glucose readings that is different from the Libre reader.
The app gets readings every 5 minutes. Here is a comparison between the app, my meter, and the libre reader:
The Ambrosia App is the lowest, when I tested it said I was at 91. The libre reader said 113 and my meter said 122. The app seems pretty consistently lower than my meter and libre reader. I’m sure there are many factors that go into the calculation ranging from the particular sensor to whatever so this may not generalize to others.
You might notice the Y axis scale on the Ambrosia app. It auto-scales based on readings. So if in the time period selected I had readings from 80 to 100 then the scale will be about 80-100 and it might look like giant peaks. I suppose this is nice sometimes for fine detail but it would be nice to be able to change the Y axis scale because generally I want to know if I’m high/low/medium and I have to think a little more by also checking the scale of the Y axis. Right now you can’t change it the Y axis scale in the app.
The trends mostly seem to match, although as I’m typing this my meter says I’m at 213, the reader says 194 with an up arrow, and the Ambrosia app is at 137 with just a slight tick up. So the app definitely seems to lag behind in terms of numbers, maybe by 15 minutes or so.
Here is one it did catch, the tallest peak below was when I got up at 7am to put the trash out (there have been bears roaming around trash diving so we can’t put it out too early) and I ate a donut hole and the app did show a 30 point rise, although I was closer to 100 to start with rather than 75.
My major criticism is the app is missing a lot of features. Want to register to share numbers? Coming Soon! Add a note? Coming Soon! Change any settings other than units? Can’t do it. The pairing process didn’t clearly indicate it had successfully paired. The biggest issue is there are no alerts in the app, which I think is the major reason you’d want a CGM, to alert you if you are low or high. I’m a little surprised this is currently missing since that doesn’t seem like a terribly difficult thing to add.
The app also chews up some battery life on my phone, although I haven’t used it enough to quantify it yet aside from it seems like my battery is draining a little faster than usual.
My feeling is in its current state all the Blucon does is save you the little bit of effort it take to swipe the reader over it. But once the other features are added, especially the alerts, it could be a pretty nice CGM alternative for a self-funded CGM at a reasonable cost. Actually, a one-time cost for the Nightrider! How often do you see one time costs for diabetes tech!
Since the blucon reader appears independent of the Libre reader it might even work with the freestyle libre pro. This was alluded to in other thread, but that should be a moot point when the Libre makes it to the US market (maybe around the end of the year).