Switched CGM Systems? What to Do With Leftover Dexcom Sensors

Almost nobody switches CGM systems on an empty cupboard. The prescription changes, the pharmacy sends the new one, and a few boxes of the old sensors are simply left over. They were paid for, they are sealed, and they are now completely useless to the person holding them.

That is worth being blunt about, because it is the whole problem. A sensor from one system does not work with another. Someone moved from Dexcom to a FreeStyle Libre or a pump-paired system has no use for the Dexcom boxes still in the cupboard, and the same is true for anyone moved from the 10-day G7 sensor to the 15-day one. There is no adapter and no reason to keep the box "just in case".

What you are actually holding

Open the bag properly before deciding anything, because a CGM changeover usually leaves more than one kind of box behind:

• G7 sensors. The boxed, single-use part, in 10-day or 15-day versions. This is almost always the bulk of what is left and the part with real value.
• G7 receivers. The handheld display. Many people never used one because they read the sensor on a phone, so these often turn up unopened.

People routinely throw away the receiver while carefully keeping the sensors, which is a mistake more often than you would expect. We don't buy Dexcom G6 right now, so check the generation printed on the front of each box first.

Do not bin them

Boxes of old sensors get thrown away every week by people who assume a system they no longer use has no value to anyone else. Check which generation you are holding before anything goes in the trash.

What makes a box sellable

Three things, and they are easy to check in a couple of minutes:

1. Factory sealed. Unopened, in the original packaging. Once a box has been opened nobody downstream can verify what happened to it while it was open, so an opened box cannot be resold at any price.
2. Not funded through a government program. Supplies obtained that way cannot be resold. This is about the funding route, not about you, and nobody is asked to prove how a box came into their possession.
3. Described accurately. Generation and box count. A figure quoted against a rough description is a figure that changes when someone sees the boxes.

Photograph the sealed boxes with the lot number visible before they go anywhere, and keep those photographs until you have been paid. Do not open one to photograph the contents — opening it destroys the only thing that made it sellable.

Where it goes from here

For a handful of boxes, the Dexcom sensor buyer page covers exactly what is accepted, how the mail-in process works, and where to find a local buyer. Mail-in works from anywhere and the label costs you nothing. The state pages list every buyer serving your state if you prefer an in-person handover.

If the switch left you with a lot — a pharmacy changing its stocked line, a supply company clearing a discontinued product, or a reseller holding a hundred pieces or more — that is a different conversation, and the bulk page is the right starting point. Mixed sensor types are normal in a lot that size and do not need sorting before you get a number.