You’d expect that with me being pretty happy with the FreeStyle Libre, new glucometer reviews would be unlikely. On the other hand, as you probably noticed as well, I like reverse engineering devices, and I have some opinions about accessing your own medical data (which I should write about at some point), so when I drop by the United States I check if they have any new glucometer being sold for cheap that I might enjoy reversing.
The iHealth Align is a bit special in this regard. Usually I just buy what’s on offer at Walgreens or CVS (sometimes thanks to Rebate just paying taxes for it), but this time I ordered it straight from Amazon. And the reason whas interesting: I found it with a “heavy” discount (the page I ordered it from is gone, but it was something along the lines of 30%), and I guess this is because the device is mostly advertised to be for iOS, and since it uses the TRRS (headphone) jack, it will not work on the more recent devices. On the other hand, it still works fine on Android.
Originally I wanted to wait to go back home to look into it, as I also bought some TRRS breakout connectors to be able to run my newly-bought Saleae Logic Pro 16 onto it, but a funny accident got me to open it while on my trip, in Pittsburgh, and try it out already.
As for the funny accident, I am not entirely sure how that happened but after dinner with Rick, after I went back to my room, my FreeStyle Libre reported a fall from 10 mmol/L (138mg/dL) to LO within two readings (and missing a few data points after that), and then reported me as being having a low blood sugar event. I was not hypoglycemic at that point, as I can feel it, so I double checked with the new meter, that showed me just fine in the 7 mmol/L range, which meant I was good. After an hour or two the self-calibration of the sensor went back to normal and it aligned again with the other meter.
My doctor suggests that the -15℃ weather outside would affect the chemical reaction, and make even blood testing unreliable. On the other hand, I had a second happening of the same failure mode after a shower last night, it might be a defect of this sensor.
I’ll start with a first impression before actually going onto the details of what I found in deeper inspection of the device, mostly out of need since I’ve started the post while travelling through airports.
The device is very small and it’s an active device: it has a button cell inside, and it comes with replacement ones, likely because they are not very common ones: CR1620 — not to be confused with CR2016! The package I got had no strips, but came with “sanitary phone covers” — I think they meant it to be for medical professionals rather than self-use, but that might explain the cheaper price.
To use it with your phone, you obviously have to install the iGluco application from iHealth, and that application needs obviously permission to listen to your microphone to use the audio jack. What surprised me was that just plugging the device in opens the application. I was scared that the application was constantly listening to the microphone waiting for a magic handshake, but a friend suggested that they may just be registering an intent for the jack-sensing, and playing back a handshake when they receive that. Plugging in a pair of headphones doesn’t do anything, and I have yet to fire up the analyser to figure out if something else may be going on.
Before you can take a reading you have to sign up for the iHealth remote service, and provide it with a valid email address. It also asks a couple of basic questions meant to be useful to track your health in general, found those a tad creepy too but I understand why they are there. It’s not surprising, given that the LibreLink does something very similar (without the questions though). It does give me a bigger incentive to try to figure out the device, although I’m also concerned it might be too locked in for the vendor. On the bright side, I confirmed all the communication with the remote service happens over HTTPS; what I did not confirm is whether the app is validating certificates correctly so don’t trust my word for it.
There is a blast from the past when I tried using it the first time: the strips are coded. I have not seen a device using coded strips in years by now. The OneTouch Ultra strips have been coded in the past, but over the past four years or so, they only sell code 25 — and they stopped selling them altogether in the UK and Ireland. To code the strips in, the strip bottles come with a big QR code on the top. This QR code embeds the date of issue and expiration of the strips, and appears to provide a unique identifier on the bottle, as the application will keep track of a shorter expiration time for the bottle when you start using it, which means it’s hard (or impossible) to use two bottles (like I used to do, one at home and one at the office).
The app includes some interesting metadata with the reading, but that’s nothing new. It’s definitely easier to write notes or select pre- or post-meal readings than with a normal glucometer, but again, this is not really exciting. It does, though, allow you to select in which measurement unit you want your readings in, whether mg/dL or mmol/L. This marks a first in my experience; as far as I knew, it is against regulation in most countries to let the user switch units, as the risk of a patient to misconfigure the glucometer makes it a deadly risk. But who am I to complain? I have written my tools because I needed to dump an Italian meter in a way that my Irish doctor liked.
As for the testing strips, they are huge compared to anything else I’ve used, although they don’t require so much blood as they may look like doing. They are a bit difficult to fit properly into the meter at first, requiring a bit more force than I’m used to either, and sometimes the app gets stuck if you don’t fit them in properly. All in all this makes it a bit of a shoddy meter on the practical level in my opinion.
From what I can tell, iHealth has a newer model of their meter that uses Bluetooth instead of the audio jack, and is thus compatible with the new iPhone models, and that may be more user friendly with regard to the app freezing, but I would expect the issue with the force needed to fit the strip to still exist.
I have not yet started looking into the communication between device and phone yet, although I have all the pieces I need. This weekend I think I’ll be soldering up a couple of things I need and then post pictures of the resulting breadboards, I’m sure it’s going to be a funny one.