FreeStyle Libre: 8 Weeks On

Here’s a video update about the FreeStyle Libre glucose monitoring device that I’ve now been using for about eight weeks.

Unfortunately three sensors have failed early. One gave some odd readings the day before and then gave an error saying the sensor needed to be changed.

The other two sensors kept saying I was dangerously low when I felt fine, but the system’s self-diagnostics didn’t detect the malfunction. I applied a second sensor and used a second reader, which showed a higher reading by about 2.0 mmol/L by the time I removed the sensor. It may have had something to do with the adhesive coming loose on the sensor – which hadn’t happened before.

Since recording the video, a third sensor has failed early, and underneath there was pronounced skin irritation (pictured below). This may be responsible for it becoming unstuck. Other users online have also found that their initial sensors worked fine, but their bodies seem to attack sensors applied later on. It’s happening in almost half of FreeStyle Libre users, and some are experimenting with a Compeed barrier between the skin and sensor. I might try this next time.

It’s also worth noting that the sensor applied most recently caused bleeding out of the hole immediately after application (also pictured below), but it hasn’t caused any issues so far.

Notice the skin irritation that may have caused the sensor to become unstuck. Also note the bleeding from the newly-installed sensor.

The skin irritation that might be linked to the sensor malfunction. Also note the bleeding from the newly-installed sensor, which did not seem to affect its performance.

Fortunately the incorrect Libre results are in a safe direction, and wouldn’t have resulted in an unsafe insulin dosage decision. However for the first time in six weeks, I have had to supplement the Libre with finger testing, as I need to be confident in my results while switching my basal to Tresiba.

Overall I still really like the Libre, but it would be amazing if it had the ability to transmit a high glucose alert (say, at 6.0 mmol/L) like a CGM. The Dexcom G6 coming in 2017 sounds like it might be a great (but expensive) alternative to the Libre. However, I’ve already got high hopes for a future Libre that might transmit via Bluetooth to an Apple Watch.

Also check out my video of applying the sensor.

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