Expired Dexcom sensors?


I am curious if anyone has a good sense of how well expired sensors work, and what their effective duration truly is. I don’t mean how many days they can function when used but how many months past their due date they can be used with good expectations.

What I know:

  • Many of us routinely use sensors that have been expired for a few months

  • Dexcom does not replace expired sensors that malfunction, but rarely asks.

Does anyone have a sense of when they truly become unreliable, and how? My sense is that it must be a progressive deterioration, where noise and signal loss appear progressively earlier.

I expect that there are numerous anecdotal stories of a really old sensor working well. More statistical understanding of the aging process would be useful.

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8th Grade Science Fair Project— Meter Noise
Expired Dexcom sensors work fine!

@Michel Honestly, I’ve never even looked at an expiration date on a sensor, but I must have had at least one be expired in the past eleven years.

And in all that time I’ve only had a couple or maybe three fail and need to be replaced. This is Dexcom STS-3 through G5 and everything in between.

In my experience I would say that Dexcom has excellent QC and is well over-engineered.

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I’ve been wondering about this too recently. Glad to hear @docslotnick’s real world experience. I’m about to try an expired sensor, so I will be able to let you know what I record.

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This sensor, like most in the space, uses an enzyme to detect the glucose. Because of this, the longer you store the sensor the more of the enzyme that will be deteriorated. Because you are storing the sensor in a dry state, less movement of the enzyme will occur, and less degradation than if it was stored wet.

Without testing, or seeing Dexcom’s data, there is no way to know how long they will last. Most companies try to get the longest dating possible for expiration based on their internal testing. Because some of this data will use non-optimal storage conditions, I would assume that you could use a properly stored sensor for quite a bit of time past expiration with no ill effect. As the enzyme degrades, your signal to noise ratio will increase.



Hey @Michel - i just used one that was expired by 4 months and I got my usual 20+ days out of it.



I realize this thread is very old but I can’t find any newer info. Like every one else, I wear my sensors much longer than recommended. Therefore, since I get automatic shipments, I have many expired boxes. I’m using G5. Does any one have info, advice on the efficacy of sensors that have expired mid 2017?
I really would rather not trash these.
Thanks for any input!

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I seem to remember someone saying something about the enzymes or something breaking down after enough time. Not sure what that time is though. Someone smart will surely chime in soon!

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yes, I saw that. Was hoping something more up to date!



Thank you though!!



So Jay, mid-2017 was a good vintage, those sensors lasted a long time for us. The issue is that the basis of the electrode is an enzyme (Glucose Oxidase) and it can break down. I would say you probably have a good chance with those based on my experiences, but they won’t last forever. I would not think so highly of late 2018 sensors.



I have used some from 2018, that worked fine. I think how they are stored may help, cooler may be better.

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not smart, but chiming in…lol

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As long as you’re prepared to swap out bad sensors as needed, I would give those 2017 sensors a shot even though they are getting pretty old…that seems to make more sense than not using them. I used some expired 2017 sensors during 2018. The oldest were about 8 months after expiration. There were no problems and they seemed to last 2-3 weeks if I recollect correctly.



Agree. I would definitely try them regardless

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Thanks to all! I will post after I have used a box FYI!



Our feedback on expired 2018 sensors is negative. However, I need to warn that in this past year our sensor record has not been good. Our average sensor life for good sensors is about 7 days.

We are now using a batch of Nov 2018 sensors, that have gone through airport scanning a few times. With this double whammy, we have been getting 3 days out of each sensor, which, is less than half what we normally get on average.

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My last sensor expired 10-2018. I used it from feb 17 to mar 10, using G4.

Current sensor (exp apr 2019) worked fine through today, (Mar10 - 24), but transmitter just ended. Will start new transmitter with new sensor.

Curious if G4 and G5 transmitters might have different tolerances of when signal shows no readings, leading to different # days of use.

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