/ Diabetes

On CGM and Hacking the Freestyle Libre Sensor

About a month or so ago, I saw a great video on YouTube that talked about new sensor readers that were manufactured and sold in China and shipped to the U.S. These readers would basically do the dirty job of scanning the FreeStyle Libre sensor every 5 minutes, much like you could do manually with the FreeStyle reader, but they worked via bluetooth. To say the least I was intrigued. Let me back up a second and give some context.

I have been a diabetic for 32 of my 44 years on this planet. A good portion of that time was checking my blood sugar with finger pricks, taking shots 3-6 times a day and hoping things worked out. Later on came the insulin pump and the 3-6 shots decreased to 1 stick every few days and a more manageable way to deliver insulin. Better. About 3 years ago I attempted to use an early attempt at CGM (continuous glucose monitoring) that works specifically with my pump from Medtronic. This went ok. I still had to calibrate every few hours (finger prick) or my pump would yell at me and stop tracking blood sugars if I didn't respond in a given amount of time. Also, its calibration was weird. I could do a finger prick and tell it what my blood sugar was at that moment (my pump actually communicated directly with the pump) and it would almost fight me at times thinking its previous information was more correct. I will revisit this a bit later. Needless to say, having only 1 device that could tell me my blood sugar (the pump) with no real ability to monitor it otherwise, the annoyance of the alert system, and the tremendous cost of sensors ($600 for 5 OTC, or about $300 with insurance all directly applied to deductible for a while), I stopped using this. I was again floating with manual finger pricks.

A few months ago, my doctor asked me the best question ever. "Do you hate checking your sugar with finger pricks?" "Of course." I said. He then introduced me to the FreeStyle Libre system. The great thing here was that every 10 days, I would insert a sensor and I could wave the reader over it instead of pricking my finger. Win! The downer is that it's new tech in the US, so you either need an exception from your insurance, or you can rely on the FreeStyle coupon pricing. This makes the sensors $75 for 3, or basically $75 a month. Still a good cost at about $900 a year. The Medtronic and Dexcom systems are around $1200-$1500 just for the sensor that attaches to the replaceable ($600 for 5) inserts. I was good with that change up. HSA covers it, so I am a happy guy.

Now I get back to the point. I see this YouTube video and I am intrigued. I take the jump and order the $200 "appliance", for lack of a better term, from MiaoMiao and wait. Granted this item has to clear customs, etc. It took between 3 and 4 weeks to get to me. Once it got here, excitement ensued. Essentially I was able to create a CGM system for a $200 fixed price and $75 a month for the sensors. Compared to other options, this was a crazy savings!

Now for the details: The reader itself is rechargable and water proof to some degree. In other words, I can shower in it and probably go into a pool. I will re-read the specs before I do that though. Pools and hot tubs tend to degrade the "sticky" that these types of items use to stay on my skin, so I am a bit more careful by that measure. It is about an inch and a half long, an inch wide and about an 1/8 inch high. I could be off, as I am just eyeballing it. I've added pics below compared to a guitar pic. The reader fits on top of the sensor (about the size of a quarter and about 2.5 quarters height) and sticks directly to it via some included double-sided stickers. Once there, the technical setup begins.

There is a video for the sensor on the MiaoMiao site and it made setup quite easy. Using XDrip+ (an Android app), I was able to connect my reader to my phone, then my Android Wear watch, within minutes. There were challenges:

  • Bluetooth is a pain. The first day or so I could not figure out the right things to tap in the setup of XDrip, so I would lose connection.
  • Calibration is still needed. This can depend on when you start reading the Libre sensor. Normal setup is 12 hours to wait, but XDrip can read it after an hour. This requires a little more calibration at the start of a cycle. The calibration can be setup differently with some additional settings. I find it to be more cooperative and helpful than Medtronic's calibration.
  • I am impatient. So if I see the reading not occuring exactly every 5 minutes, I fiddle with the settings and I mess up the bluetooth. See the first challenge.
  • The first week to two weeks with this thing is scary. I have never had continuous knowledge of my blood sugar on my watch, in my pocket and just there to look at trending data any time I want. Scary is the word. I started over-reacting to highs, which created lows. The data is all encompassing. Finding out what pizza does to my blood sugars and exactly how long it takes to balloon it up freaked me out and I may never eat my favorite thing ever again.

With those challenges comes some definite positive things:

  • There is a ton of data. Yes it's a challenge, but knowing your body better, once you deal with the initial freakout, is a good thing. After 3 weeks, I rarely see higher than 250 or lower than 70. I expect in 3 more weeks that window will tighten. Before, I had no idea what the window even was, but I would see 300+ and less than 60 all too often.
  • Using XDrip, calibrated to finger pricks, I no longer really have to use the FreeStyle reader. That means I can extend the life of my sensors past 10 days. The first one I attempted this with came out today at 14.5 days. If that is how things will go, 3 sensors last a month and a half and my monthly cost goes from $75 to $50 for sensors, or $600, paying for the MiaoMiao in the first year.
  • It's taught me to be more patient with my body. Nothing is immediate when it comes to treating diabetes.
  • XDrip is open source software. I am supported by a community of diabetics. It is robust and can be used for far more than I use it for. It is updated often with good documentation.
  • As for bluetooth issues, once you figure out the right things to do when there is a missed reading, it takes seconds to get things back on track and these incidents became far more scarce the longer I wore the device and just trusted the software to do its thing.

Overall, this is a great setup. It is not as clean or easy to setup as Dexcom, because it's a hack of sorts and Dexcom is an out of the box (albeit expensive) solution. I would suggest anyone with diabetes to follow Nerdabetic on Instagram and Youtube, especially if you have an iPhone/Apple Watch combo. Please let me know if you have questions I didn't answer here and if you jump on board, I'd be happy to help you get started, even though I will insist you attempt to set it up and get it going yourself first. It helps to know you did it and to learn the settings along with all the bells and whistles.

Here are the promised pics. First is the Libre sensor and then the MiaoMiao reader.