Dexcom Sensor Errors/Bloody Insertion

So, I’m hoping I can get a little insight as to whether or not anyone else has experienced what I’ve been dealing with with my Dexcom G6 lately.

Let me first start by saying that when the sensors work (which was 100% of the time until December), I am absolutely in love with them. Recently though I’ve gone through entire months’ worth in a week’s time because of sensor failures after warm up. Thankfully technical support has been awesome and replaced all of the faulty equipment. Last night though, I went to put on a new sensor and pair a new transmitter at the same time, and had a really bloody insertion. I’m not one that gets squeamish about that normally, but it freaked me out as I had never seen one bleed so much. It covered the entire interior surface area of the sensor and I was able to dab it with a paper towel through the cradle. At this point I started to turn white from the panic and had to lay down with an ice pack. (I did notice the blood starting to dry, so I snapped in the sensor and started the pair and warmup process before lying down.) It warmed up just fine and gave readings for about 30 minutes before I started getting sensor error messages. The first was at 4:30am, then it came back and immediately shut off at 5:00am, and again at 6:30am. The last reading matched up within 2mg/dL to my backup meter, but I’m still worried I’ll need to switch the sensor already. It’s a brand new box, but I’m worried I’ll keep running into issues waiting on a replacement from Dexcom. Another couple things of note:

  1. All the sensor errors and failures have been 3ct boxes from my pharmacy, whereas all single boxed sensors from Dexcom have worked normally, and
  2. I think most of my issues are cropping up when I do an insertion on the right side of my abdomen. I only use abdomen sites and go back and forth each time (left side for 10days, then right for 10). Has anyone else experienced this? Technical support has asked me if I’m extremely thin, but I’m not. I’d say I’m average as far as that goes. I also noticed bruising around the top left corner of the sensor pad when I got up to test manually about an hour ago.
    Anyway, sorry for the novel, I just wanted to make sure I got all the information out there. I’d love to hear input on the topic!

Thanks for reading!

I am not yet on G6 as medicare is going to start converting us G5 users around April 2019, however, I sleep on my sides and when using side of abdomen insertions and my transmitter gets buried into the mattress, CGM readings drop about 25 points and give me a hypo alert. Turning so that there is line of sight between transmitter and receiver promptly corrects this error. I have heard rumored that with the G6, under certain conditions it will error rather than show a bogus reading. Could this be one of those instances?

In order to correct this issue with the G5, I exclusively use 2 insertion points on abdomen. Both positions are inline with belly button and sternum. One week is inserted in high position, just under sternum xiphoid process and the next week low, just above the belly button. There is enough real estate there to allow each insertion point to recover for a few weeks at a time by moving top to bottom or left to right by 1/4 inch or so.


Dex Tech Support will replace sensors that have excessive bleeding without requiring to wait for a sensor failure.

Judgement call what is “excessive”.

If we get a small pencil eraser sized dot of blood in the middle of the sensor/patch during insertion (or less) then we consider that very good and continue on with snapping the G6 transmitter in.

If we get the entire patch soaked then, first, yes, lie back on a bed and chill for a few minutes. I am not going to bother snapping the transmitter in with a fully soaked sensor patch. Dex Tech Support has always replaced those with no issue. Some times they want the sensor returned and some times they do not want it. No difference to me either way.

A partially soaked patch is the judgement call. We would probably try to use it with up to maybe 2/3 soaked from a bleeder.

I doubt whether or not a particular sensor insertion is going to result in excessive bleeding has anything to do with where you source your sensors but that is only a guess on my part.

We do not get many excessive bleeders but the ones we do have appear to be on the front/side of the torso and almost never on the upper buttocks / lower back. We have also used back side of upper arm a few times with good results.

We do not often get compression lows with the Dexcom. But I have seen them on the G6 so they still happen. It is pretty obvious when it happens but for us at least, they are extremely infrequent.

So the question is with a compression low, for example, on the G6 do you just get the bogus low reading or does the G6 error out or do something else?

Thank you


Sorry if I was not clear.

When I say an obvious compression low, I am talking about a sudden and significant downward movement in G6 cgm data followed by a return to expected cgm data when the sleeping body is moved to a new position. The return to normal is a bit slower than the speed of the drop.

On the rare occasion that this happens for us, it is blatantly obvious when visually looking at a cgm graph.

A Dexcom error can mean many things and likely has many situations that cause the cgm to go into error mode.

they asked because if what they told me is true, the G6 is problematic for those with little body fat. The G5, according to them is far more suited to those with lower body fat. They did not give me any BMI info regarding the issue with the sensors–just that the G6 doesn’t work well for many that are very thin. I have no personal knowledge as I’m using the G5–I’m only recounting what I was told, so a heads up those who love to argue with nearly everything I write here. :slight_smile: (I say that because apparently I swim against the “tide”. I get very few “likes” and when I write something in a thread, which is echoed by someone else, their post(s) will get the “like” and mine won’t. So I’ve concluded that I’m hardly popular on this site. But that’s OK. It’s just an observation)

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I use the G6 sensor on my abdomen as well. For some reason I get more compression errors wearing it on the left side than on the right side.

I’ve never had a bleeder, but I do often get false lows right after the sensor warms up and calibrations are rejected. The first time it happened I called tech support and they couldn’t have been nicer. The tech said I could put in a new sensor and he’d send me a replacement, or I could leave it alone and not try and calibrate (it was bedtime) and see if it started working overnight and he’d send me a replacement. When I woke up it was working just fine. Guess it needed a little extra time to get going.

Last week I had a sensor at the end of Day 9 throw up a “temporary error” for about 30 minutes and then start working. It spent the 10th day doing that intermittently. The next sensor gave off the false low at warm up, it asked for calibration and then wouldn’t accept the calibration and just kept asking for a calibration. Normally I would have just gone to bed and called it a night and see what it was doing in the morning, but I had just started on the pump a couple days before and the low triggers a suspension of insulin. Finally I just turned the Basal IQ off on the pump and went to sleep. Woke up and it was working fine. I’ll be replacing them in the morning from now on.

Hi, I currently use the G6. I had several times where I had to completely change the transmitter, which to me is a waste, because of a malfunction. The good thing about this is that Dexcom will always send you a replacement via FedEx free of charge. In the beginning I had at least 3-4 failures. This was very frustrating. I now have not experience a failure for awhile. After speaking to Dexcom professionals, and others who are involved in the making off apps - they are often sent to market with kinks. It appears that the G6 may have been released before it was completely ready.

I had a bloody insertion about a month ago. It is recommended that the G6 be inserted around your abdomen. I do not calibrate often, but when I do it’s mostly in line with my One Touch device. The numbers also mimic what my A1C is. I have never had a compression low, or maybe did not notice it as such.

What I noticed that was different about that insertion was that I had pressed down extremely hard using the device. The next time I did not press down as strongly. I would suggest maybe being gentler with the insertion.

I am still on a G-5 considering going to the G-6 soon, although I am hearing a number of concerns about erroneous readings like this. I did want to comment on the bleeder, though. I had one of those with a G-5 insertion and it lasted for about 2 hours after it warmed up then gave me an error message and then then the sensor failed message. Of course that took place around 1 am! I did call Dexcom right away and they sent me a replacement, but the agent confirmed that yes, a bleeder will interfere with getting a clean reading and will almost always fail.

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You probably just hit a vessel. I’d be surprised if it happened twice in a row.

A few days ago, I inserted a new G5 sensor around 1 pm. All was well until I went to bed and noticed quite a bit of “fresh” blood around it but it was still working and running a bit high. The following morning I replaced the sensor (and Dexcom said they would send me a new one.) I wiped the transmitter with an alcohol swab as per usual. The next two days the numbers coincided with my pump very well but now on day 5 there is quite a discrepancy (up to 4 mmol). Is it possible there is blood within the transmitter? Any other way of cleaning it?

No. The transmitter is hermetically sealed. You could drop the thing in a pool of blood and it would be fine. Assuming you subsequently cleaned the contacts.

Cleaning the transmitter contacts with an alcohol wipe has also been our process.

With the G5, you can easily pop out the transmitter on Day #5, clean the transmitter contacts, let it air dry a few minutes then pop the transmitter right back in. See if things improve. For us on the G5, sometimes that would help and sometimes it would not. Always worth giving it a shot as there is no downside.

The accuracy issue with your current sensor has nothing to do with the previous sensor.

And we have just learned how to pop out the G6 and put it back. Just tried it for the first time as practice and it worked awesome !!!

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G6 Transmitter removal from active sensor

I have had that happen with a site that had a lot of blood on it. In most cases the sensor fails before its normal time frame or it is incredibly inaccurate. When I have removed it, I have found dried blood coating the thin wire which appears to have interfered with the sensor’s ability to get an active interstitial tissue reading.

I know this thread is older but I’ve cut down on the sensor errors due to bleeding by always inserting the large end facing down. That way if I’m standing or sitting with the insertion area bleeding some it will not run down to the electrical contacts as they are on the narrow end of the Transmitter. Doesn’t completely prevent the issue but helps a lot. I found that with 2 test strips I can pull of the transmitter; then clean the sensor top with some water and use tissue to blot dry without removing the sensor. Then clean the transmitter and plug back in. Don’t take too long doing this though as it may be seen by the receiver and phone as a failed transmitter.

I have sometimes had some bleeding I find when I remove a sensor but never had it affect readings. I have some sensors that work perfectly but then batches come in that fail badly for 1 or 2 days. If they fail longer I get them replaced. Often the ones that read way off on day one or 2 will work extra good for 20 days after that.

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