Dexcom lot dexcom full of sh**?

Hi guys

Been on Dexcom for around 7 years. Had my fair share of failures, usually sensors that never make it to the 7 day mark.

  1. Recently, had a transmitter that I replaced the battery in, everything was working ok for about a month.
  2. After a month, numbers on my X2 Slim graph start to get a bit wonky and jaggety (not a smooth line). For example, line would be at 6.0, 6.0, 6.0, all of a sudden jump up to 6.5, then jump back to 6.2, 6.0.
  3. Couldn’t figure out what it was, kept happening over multiple sensors.
  4. Put in a brand new transmitter Dexcom sent me. Transmitter wouldn’t connect at all.
  5. Dexcom sent a replacement transmitter, the same one I’m using now. Graph is still funky, no smooth lines at all. Sensors mostly all from the same lot #7269439 (G5).
  6. Dexcom is going to replace my 3 sensors and give me a new transmitter to try, but they refuse to exchange my still brand new 9 sensors that have the same lot numbers as the ones that failed. Lady tells me that the “lot number” is just something for internal use and has nothing to do with when the sensors were made or if they’re from the same batch.

From what I had thought, and what is normal practice throughout most companies, a lot number denotes the “lot” from which the sensors came from, meaning that they were all produced in the same batch. Am I wrong in this thinking? Or is Dexcom just giving me their BS lines?

They told me that they would only replace the sensors if they’ve failed, and that I will need to try out the next 9 sensors (even though they will likely fail in the same fashion as the last 3 with the same lot number). Pisses me off that I will need to stab myself 9 more times meaninglessly just to prove that they’re bad.

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There could be hundreds or thousands in same lot#. More likely your shipment may have been exposed to high heat during shipment or at distribution center. Or could have been problem at manufacturing, but no way to know.

How long have you tried waiting for readings to settle?

Could be. The sensors go until they fail which is roughly 3-4 days after installing. The readings never settle from the beginning to the end. :pensive:

I assume you are outside US. In US, Tandem users call Tandem, even for dexcom sensor problems, since pump is processing data from dexcom. Maybe give tandem support a call.

Thanks. You’re right, I am in Canada. Dexcom had told me the same thing. I tried contacting Tandem first today but was on hold for 30 mins before I gave up and called Dexcom. Maybe I’ll give them a ring.

Here is a picture of my graph, just for reference. Does this seem more like a transmitter or sensor problem to you guys?

It’s never perfectly flat for me. I’m not sure I understand what timescale you’re looking at when pronouncing the curve as being jaggety.

My first day on a new sensor is a little jaggety. Typical first day:


Typical a couple days later it seems a bit smoother. I think the transmitter “learns” to smooth the sensor noise after the first day. I think the transmitter does the smoothing and not the receiver but I could be wrong.


Again neither is perfectly flat and some of them are probably me rolling over onto the sensor then off again.

P.S. OK neither of those curves are really typical. They’re actually really good bg’s for me. Here’s a bad overnight. But those features you see on this graph are real bg, not sensor noise:


How many hours is that bottom scale? Is that the first day on a sensor or a subsequent day? Do you have a Dexcom or phone receiver and does it show the same thing?

My best guess is that jumpy BG graph is caused by the sensor not the transmitter. That 3 hour graph indeed shows what I call jumpy BG readings. My G5 sensors start to give jumpy readings like that when they are close to their end of life. Usually 14+ days after insertion. Occasionally dehydration will cause the sensor track to get jumpy, in which case it smooths out and recovers as I get hydrated. So I will sometimes let it ride for a day or so and hope the sensor recovers. But jumpy graphs like that after about 2 weeks don’t usually recover on their own, and I replace the sensor when it happens.

This may or may not be helpful, but one of the things with these CGM tracks is that they are normally “smoothed” before shown in the graph, with an algorithm that eliminates what it interprets as erratic data points. Haven’t used it for a while but xDrip gives (gave?) the option of showing the graph without smoothing, and the raw version is bumpy and noisy, much like what you’re seeing here. Dunno if there’s some kind of software fault that can cause smoothing to switch off but the similarity did strike me so I thought it might be worth mentioning.

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Scale is 3 hours. You can tell it is way more erratic compared to yours. Yours is what I normally have.

Yeah, that’s what it seems. Very strange…

For starters, I would double-check that the transmitter has clicked twice into the sensor (both sides). Otherwise, moisture can get in. It’s also possible the transmitter has been scratched, letting moisture get into the connection.

The other thing I would suggest trying is a different sensor location. In my case, I get much smoother and accurate and longer sensor use when it is in my arm rather than my abdomen. However, the downside is that I occasionally lay on my arm, which results in compression lows/errors.

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This is an interesting problem that I have never heard of.
My first suspects are: 1.) Problem stemming from the Dexcom app ( I assume your running this on your cell phone) or a mix of cell phone software/hardware and the Dexcom app; 2.) X2 Slim graph - whats this? Possible T:slim bug?

This feels like a software problem, not a hardware problem.

But, I like the moisture idea.

Could try installing the Dexcom app on another phone, like your wife or girlfriends…just to eliminate some variables?

This data looks perfectly normal to me. This is typical Dexcom data output. I’ve seen data output like this for over a decade. I declare this a non-problem, unless you can volley back contradicting me, lol.