What you’re dealing with
Continuous glucose monitors communicate over Bluetooth Low Energy, which means both the sensor and the reader broadcast and can be detected.
| Broadcasts as | Dexcom, FreeStyle Libre, and reader device names |
|---|---|
| Typical battery | Readers last days; sensors run for the wear period |
| Findable by scan | Yes, while powered on |
| Search window | Hours, act today |
Once the battery is gone: A reader that has run flat stops broadcasting. If the reader is the missing piece, charge is the first thing to rule out.
Where it usually is
Bedding and bedside tables
Checked overnight and put down.
Bags and coat pockets
Carried everywhere, which means it can be in anything you wore today.
The bathroom
Checked and left on a shelf.
How to search for it
- Check the last-seen map firstBefore you search a room, find out which building. A pin saves you from searching the right way in the wrong place.
- Scan from the middle of the roomNote everything that appears, then select the device you want so the rest of the list drops away.
- Walk and watch the signalSweep in a straight line, give each position a few seconds, and turn 90 degrees when the reading stops rising.
- Search inside things, not across themA strong signal with nothing visible means it is underneath or inside something. Fabric and metal block Bluetooth badly.
Tips specific to glucose monitor
- If your phone is the reader, the sensor still broadcasts and can be picked up on a scan, useful for confirming a sensor is still in range and working.
- Save the reader under My Devices so its last-seen position is always recorded. For a medical device that is worth doing on day one.
- Keep a charging routine. Most reader losses are actually flat batteries rather than missing hardware.
Other things people lose
The same method applies to these, with different battery windows and different hiding places.
- How to find where you parked, Vehicle battery
- How to identify a soundbar on Bluetooth, Mains powered, always on
- How to find or identify a smart scale, Months on AAA cells
- How to find a Windows laptop by Bluetooth, Up to a working day in use
- How to find a Bluetooth card tracker, Three to five months
- Save the devices you care about, My Devices tab
- How to scan a room for hidden Bluetooth devices, Method
- All device guides, the complete list
Common questions
Is it safe to scan for a medical device?
Yes. Scanning only listens to the advertisement the device broadcasts openly. It does not pair, connect, or interact with the device in any way.