Dexcom sensors arriving during "heat dome"

I live in MA which is going to be suffering through a “heat dome” over the next few days with temps of 96 degrees and heat indexes of 106 degrees. Of course, my Dexcom sensors (which have already been shipped) are due to arrive tomorrow, at the height of the heat wave. I may or may not be home to bring them right inside, but either way, my concern is that the sensors will be toast on arrival after baking on the hot UPS truck all day. I called UPS to ask if they can hold the package at their nearest facility so I can pick them up, but they said that wasn’t possible for this package and told me to contact the sender (CCS Medical). I contacted CCS Medical and they told me there was nothing they could do either since the package has already left their hands. So I’m basically SOL, since the sensors aren’t supposed to be kept over a certain temperature and it should be a nice balmy 120 degrees inside the UPS truck tomorrow. Dexcom hasn’t responded to my inquiry yet about what to do—but I’m concerned about using potentially unreliable sensors that may be damaged from heat through no fault of my own. Have any of you ever dealt with this before? Did Dexcom proactively replace sensors that arrived during an extreme heat wave?

I live in Texas and your forecasted temperatures are just SOP from May through September. I have never had an issue with the sensors not working when exposed to the heat in the UPS unairconditioned van or on the porch in the afternoon Texas sun.

I don’t think that kind of temperature can damage the reagent on the sensor. I would be more concerned about the adhesive being damaged, but I suspect that would take more than a few days.


I wouldn’t worry about that. The sensors are exposed to 98.6 degrees when you are wearing them!


I understand your concern, but I wouldn’t worry about it too much. The temperature outdoors is only slightly higher than the recommendation, and I imagine that you can call and get a new batch from your supplier or Dexcom, just make sure you keep all of your packaging and emails.

From Dexcom

Storing your sensors:

  • Keep in its sterile packaging until you’re ready to use it.

  • Store at temperatures between 36°F and 86°F.

  • Storing outside this range may cause inaccurate G6 readings.

  • You may store sensor in refrigerator if it’s within temperature range.

  • Store sensors in a cool, dry place. Don’t store in parked car on a hot day or in freezer.



Ya, I live in MA, too, and those temps are pretty balmy compared to my office in Delhi and other parts of the world that are at 109 degrees right now. I have never had any temperature issues with sensors/transmitters, but once during the Summer, I lost a load of insulin; UPS put it on my doorstep, facing directly into the Sun, and sat there for a week baking while I was overseas. Insulin is the only diabetes related item I have ever lost due to heat.

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Gotta remember that recommendations from the manufacturer just indicate what their testing conditions were. It does not actually mean the product self-combusts outside that range, only that the sensors weren’t tested for accuracy at any other storage temperature.

There is an enzyme on the sensors, glucose oxidase, which could definitely be damaged by extreme temps. Low 100s isn’t extreme, though. Glucose oxidase is stable all the way to 76°C/168°F, possibly higher. So I wouldn’t sweat it, personally.

The same rule apply as always. Fingerstick if you don’t trust the CGM and/or if your symptoms don’t match the data. If it’s inaccurate, Dexcom will replace it. Don’t provide any more info than they ask for.


@hollymateluber’s concern is valid and I agree that the UPS warehouse and truck are going to be hotter than a snakes butt in a wheel rut. I hope she posts Dexcom’s response.

I will share in my personal experience like others here I live where 90 is a lovely spring day and I don’t give two thoughts to leaving my dexcom delivery on the porch all day till I get home. I have been out in the 110s and the G6 did stop giving readings. I can’t remember the error if any. The manual says the transmitter operational range 50°F–107.6°F. My wild guess is the 86° is about the pressure sensitive adhesive.

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While your concern is valid, most people forget that the heat index is not the same as the temperature. The heat index is like the wind chill, and is what the humidity makes the temperature feel, but is it has nothing to do with the temperature. It might feel like 120 degrees but a thermometer will read high 90’s. Humidity has a weird effect on the skin and will make things feel hotter or colder than the actual temperature.


I live in Arizona. Been a nice 111 degrees. I pick up my insulin at my pharmacy. Too nervous for it to be shipped even if packaged correctly.

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Here’s the simplest answer: use the sensors you receive, however keep the box of each sensor you use/insert. If a sensor fails in under 10 days, contact Dexcom Tech Support. They’ll want the lot number and other data from the box. They might even ask for the failed sensor to be sent back to them.

If you have not taken loads of acetaminophen, if you put the sensor on properly in an approved location, then they should replace it. Doesn’t matter why it failed, and you shouldn’t presume - as others have pointed out - that heat index in your area is the cause. (Lord knows they replace many of mine because the glue doesn’t hold and they come out, insertion hits a capillary and the bleeding interferes with readings, the readings are consistently off-base even with calibrations.)

If the tech representative insists they won’t replace a failed sensor, you can insist on speaking with a supervisor.

These sensors are not bulletproof, but they are expensive - even with insurance. Hold Dexcom accountable, just as they hold patients accountable for proper insertion, etc. Over 10 years, they have always seemed reasonable (at least to me) to deal with.

Climate change is happening, companies in the science/medicine/technology space know this, and if they need to make improvements to their products to match our changing environment, that is all the more reason to let them know their products fail. It is up to the company to figure out why they fail (heat index or other) and how to make the product reliable.

Does anyone remember that G4 sensors used to ship in cold packs? And then one day they didn’t, without any explanation.