System check passed?

I just place a new sensor yesterday. The first 24 hours do not correlate well and I try to only calibrate when the sensor is more than 30 points off and only with a sideways trend arrow.

So I woke up this morning with a 126 mg/dl reading and a fingerstick of 95 mg/dl. So I entered the 95 as an unrequested calibration. Then a few minutes later the receiver requested another calibration. I entered 95 again and the displayed number adjusted to 93.

The next thing I know the receiver vibrates and displays "System Check Passed" with a big green check mark. But all the previous data points have now disappeared. I have not had this happen before. I've got a call in to Dexcom technical support to find out what this is about.

I uploaded my data to the Studio program shortly before this happened. I wonder now if I upload to Studio again, will this clean slate over-write my previously uploaded data.

Does anyone else have experience with a "System Check Passed" display? I have the 505 firmware update.

I had that happen to me last week. I called Dexcom and the rep told me my receiver had rebooted itself but it was nothing to worry about. I do a lot of welding at work and that was probably the cause. Just my experience.

It seems to be random. I've had it happen with no ill effects a few times. I once had a dying receiver that was out for a few days, and randomly showed "system check passed" and worked for another sensor before totally dying.

Huh. Well, page 143 of the online PDF of the "Dexcom G4 PLATINUM User’s Guide" has the following very brief remark about the System Check screen.


This screen means the system found an error that it was able to fix. Press the SELECT button to clear this display, and continue your sensor session.

Maybe you can squeeze something more out of Dexcom when you talk to them such as what the heck might have happened to cause your monitor to reset.


I have had this happen once and I thought I lost all the data. But I plugged it into my computer and downloaded to Studio and although the receiver didn't show a line, the Studio did. If you do a hard reset putting a pin into the hole in the back of the receiver it should show you your data again. If that doesn't work you can also try shutting it down and restarting it.

I've had it happen twice now, but I've not called Dexcom.

Thank-you for the quick replies. I've already answered one of my questions. I plugged the receiver to do a data upload and it simply appended the currently displayed data points to the pre-existing ones.The data line is much smoother and is within two points of a my fingerstick.

This receiver is about one year old but has otherwise performed well. Andy, I hope this doesn't mean my receiver is about to die. I'll wait and see. I have a new one in reserve.

John - Thanks for the cut and paste from the manual. I should have checked there first but it doesn't offer much info. I'm still waiting for the Dex return call.

wilne - It's good to know others have experienced this, too. Do you have the 505 update, also?

Clare - Thanks for the reminder about the hard reset. I don't feel I need the old data on my screen. I'm happy it's all in the Studio program. Plus I have a screen with a nice flat two-hour line 93-101. Looks pretty!

we are seeing a lot of this recently on the CGM in the cloud group over on FB. The data is still there and if you do a shutdown and restart not a stop sensor it will come back, you do not need to do a hard reset to get it back after a system check. Have been seeing a lot of error 67 s reported as well that can lock up the receiver. You can do a hard reset with paper clip in hole in the bacl. need to put on a charger that works for about 15 minutes before doning it. leave on charger as it goes through a reset.
They say there is a hardware error that may lead to impending doom and are replacing.
Some have been able to get tit back and keep it running till out of waranty.

mine did that a few times 2 years ago and is still running fine. Dont know if thewy are having QC issues with the older models or what.the one that had the issue 2 years ago is running in my nightscout rig so does not have a lot of jiggling of ports/cables.

Wonder if the increase in reports has more todo with dry winter air/low humidity in homes and increased static discharges as people pile on the layers.

Terry, if your interested nightscout has just gone live with a version that lets you see the dex raw data, as well as the masagged number that it displays. you can see the readings it gets when the ??? or the warmup pie is showing. Has been interesting. you can see when the 505 algorithim switches from filtered to raw. its part of why it usually picks up on changes faster than the old algorythim

Yes...I do have the 505

Thanks for the feedback, hobbit. I'm gathering parts to assemble a Dexdrip system. I'd be interested in a wrist-watch display and an iPad display for night-time use.

I love that the users have taken it upon themselves to help themselves with systems like the NightScout. I think it provides more motivation for the manufacturers and regulators to speed things along. It's exciting.

katie - I'm still waiting for my call-back from Dexcom. Perhaps they're short-staffed due to the Presidents' Day holiday in the US. I'll post their answer when I receive it.

I have the drip soldered together, but am a bit slow /confused with the build the program part, will be getting help with that one of these weekends soon. Dealing with CMD prompts and figuring links and pathways when the videos don't quite match what I'm seeing is a bit of a problem. Am sure there will be help when I decide to ask!

Good for you! You're two steps ahead of me. It would be interesting to read a post of your experience with the NightScout and DexDrip systems here at TuD. I'd like to read it anyway.

I've been following the CGM in the Cloud FB group. I'm a reluctant FB user but I can't resist some of the things going on there.

Always calibrate when it's time. Always. Even small amounts matter because it tells the Dexcom which way the BG is moving whick is the main purpose of the Dexcom. Without this data you will end up being worse off.

Terry, one suggestion of help. Always calibrate. Remeber, the Dexcom unit does not read your blood glucose. It reads other fluids in the body that change as your BG changes. It's the changes that allows it to estimate your current BG correctly. And it needs to know if it's reading the changes correct or not. So if you don't calibrate, even if it's only a slight different or even perfect, then the unit does not understand the changes that will be occuring over the next 12 hours. You could be way more than 30 units different within an hour if you don't calibrate. Always calibrate.

Hi Scott - Frequency of calibration always seems to get a range of opinions here. I've settled into trying to only calibrate when the system asks for it (about every 12 hours) or if my fingerstick is greater than 30 points off and when the receiver indicates a level arrow. Are you recommending a more frequent calibration regimen?

After the "system check passed" event my CGM line smoothed out and correlated very well with the fingerstick BGs. It's as if the lumpy lines in the first 18 hours of my new sensor and all the extra calibrations made the system reboot due to its confusion.

I'm still waiting on my Dex tech return phone call. I'll update when that happens. Thanks for your comment.

I called Dexcom again and was able to get through to a tech-rep. He explained that the system check passed display can be induced by a static shock that is common in heated homes in the winter. That doesn't fit my living situation as I live in the SF Bay Area and the humidity is usually around 50%.

Anyway, I understand that this error is a system recovery response to an environmental stimulus. He also said that this is a more common error as a receiver ages. My receiver is 11 months old.

Great to actually get a reasonable explanation, even though it doesn't necessarily fit in your case. Here in the frigid northeast I am expecting to see the system check display and also the pod failures increase as the static electricity increases.