Dexcom out-of-range and ANT errors

I have started to get lots of out-of-range error warnings and missed readings even when the sensor is within about 12 inches of my Vibe. I assume that this may be a transmitter problem. My current transmitter is about 7 months old. My first one lasted 12 months and although it generated a battery warning when it died, I didn’t notice a signficant loss of range even at the end.

As I am self-funding and a replacement costs £300, I would prefer not to order a new transmitter if this is not the problem. However, I will be going on holiday next month and don’t want to find myself with a failed Dexcom transmitter.

Anyone with experience of this? I suppose I could order a replacement as a backup but Animas start the 6-month warranty from the order date, so I would be running the clock down on the warranty.


What did Dexcom tell you when you called them and asked about this?

I order transmitters when the warranty expires; in other words every six months. My last transmitter lasted 7.5 months. My longest lasting transmitter was 9 months. Even though my warranty expires doing this, I always have a transmitter on hand to immediately replace a failed one. Insurance pays for 80% of my transmitter cost.

If I were self-funding, I would seriously consider waiting until the receiver warning happens. If you pay attention to that and make an immediate order, you should be OK. I’m in California, about 500 hundred miles away from Dexcom headquarters. I usually receive shipments 2-3 days after my phone order. If your Dex source is equally responsive then this plan could work.

Since you place importance on your Dex working during holiday, perhaps you could order a replacement, bring it along with during the holiday as a backup. I did that on my last holiday. The new transmitter, in its original box, is small and light. The only real danger I see in this plan is losing the transmitter during your travel.

Next time you change your sensor site, I would take extra time to clean the two contacts on the bottom of the transmitter. Dexcom recommends isopropyl alcohol. I’ve also used a clean pencil eraser followed by the alcohol or even just soap and warm water.

Perhaps I should have mentioned this first. Are you sure your transmitter is fully seated into the sensor pod with both wings holding down the transmitter tabs? Sometimes the location of the sensor does not give a clear line of sight to see that the transmitter is fully seated. I use a mirror if I’m not sure this is true. Listening for both clicks is key when seating the transmitter.

Now I know that the user manual warns against doing this, but when I see data dropouts and loss of signal, especially when it occurs after a shower or bath and I’ve visually confirmed that both sensor pod wings secure the transmitter, I will actually remove the transmitter from the sensor pod, thoroughly dry, with a hair dryer, all the surfaces and then reseat the transmitter. This can be awkward to do, especially without the lever that’s present at initial installation, but I’ve done it several times. It involves pressing firmly against the sensor site while listening for the " click-click." Getting help from someone else would be easier. There is a danger of moving the sensor wire under the skin and ruining the site but I have not experienced that yet.

Good luck! Please post whatever you decide to do or discover.

I was on day 3 of my sensor a couple months ago, with the Dexcom in my pocket, when I got the out of range warning. It lasted about two hours and then started working again and worked fine after that. Dexcom support could not offer me an explanation. That’s the only time it has happened to me.

Thanks to everyone for helpful comments:

Because I use a Vibe and obtain my Dexcom kit from Animas, I have to go through the Animas helpline (calls are diverted to Animas USA). I haven’t yet contacted them about this particular problem (see below for explanation).

Terrry: I am aware of the need to make sure the transmitter is properly seated and that the contacts are clean and dry. I have had problems on a couple of occasions with this in the past and sorted them essentially as you suggest. When this happens you get apparent drops in BG reading or the dreaded ??? but not out-of-range warnings. The transmitter is an A-D converter that “reads” the analog current output from the sensor and transmits the value digitally to the receiver. If it is in bad contact with the sensorthere may be erroneous readings, but should not effect the power output of the transmitter. Logically, the only possible causes of a reduced transmission range are lower output by the transmitter or (less likely) a fault in the receiver (in my case the pump itself).

I will probably go along with your idea of ordering a spare transmitter before going on holiday. Animas UK are pretty efficient in sending out emergency replacements (at least of pumps). However, when my first transmitter reached the end of its life it did so less than 24 hours after the first “Low Battery” warning - not enough time for delivery of a replacement.

My concern about losing time off the warrantly period is less that the replacement transmitter may need to be replaced prematurely and more down to my last experience with Animas in dealing with a Dexcom problem. A few weeks ago I had a “classic” sensor failure. Inserted new sensor, started fine but after about 18 hours readings dropped to 2.2 mmol/L, with alarms going off and keeping me awake. After about 2 hours it recovered, then repeated the process the next day. When I phoned Animas they first asked me to make sure the transmitter was properly attached (it was). They then wanted to know how old my transmitter was. When I said just over 6 months, the response was that “Dexcom recommend you replace the transmitter after 6 months” and they were rather unwilling to take things any further. It took about 45 mins on the phone, explaining that the last sensor worked well, reading out ALL of the warning codes listed in the Sensor History etc. before I could persuade them that they should send me a replacement sensor under warranty (which is the reason I phoned them in the first place).

I suspect that Animas support are relatively less familiar with the Dexcom. It is possible to order Dexcom supplies from Dexcom’s UK representatives, however, their prices are around 30% higher than Animas’ and I would have to raise a new prescription, so it’s not worth bothering.


Press “Shutdown” on the receiver and then restart it. This fixed my out-of-range problem.

Hmm? I don’t have a separate Dexcom receiver. Maybe if I close the connection with the Dexcom on the Vibe and then pair it again it will sort the problem. Worth a try anyway.


Pity. It sounds as though you are on the bleeding edge of working with the Vibe. Was a separate Dexcom monitor omitted because you obtained your CGM as part of a package deal with the VIbe?

In situations such as this it would be nice to be able to test with another receiver just to isolate whether the problem is most likely with the transmitter versus the Vibe. Especially since the Vibe is new and thus potentially a more likely suspect, perhaps?

For whatever it’s worth, I was curious what the heck an “ANT error” might be. The first thing which popped into my head was “ANTenna” which both did and did not seem a possible fit. So I Googled and found the PDF (link below) among the hits.
Dexcom G4 and Vibe Insulin Pump Icons

The explanation given for ANT is: There was no communication between the pump and CGM Transmitter within the last 5 min.

A bit vague, but perhaps understandably so? :confounded:

The Dexcom CGM system is available from Animas as an add-on to the Vibe pump and comprises, sensors and transmitter only. . The pump and consumables are funded by the NHS. Most people have to self-fund CGM. You can also purchase the G4 system as a stand-alone through Dexcom’s UK agents. However the Animas startup kit is £500 compared to £1325 for the complete kit from Dexcom because Dexcom charge an outrageous £650 ($1000) for the receiver AND you have to pay for cables, chargers etc on top of that… Also, Animas charge £46.50 per sensor compared to £62.50 direct from Dexcom making running costs around a third less expensive.

Although the Vibe is new to the US, it has been available in Europe for about 3 years, so I imagine that the technology has bedded in reliably. Given that one of your transmitters needed replacing after 7.5 months and that’s about how old mine is, it seems that I was perhaps lucky to get 12 months out of my first one. I think maybe the problem is more that the Animas helpline (accessible via a UK 0800 number but based in the USA) still have limited experience with the Dexcom.

I assumed the ANT error was standard and that anyone would know what it meant. As you have guessed, that’s just the symbol that comes up on the CGM screens if the pump loses communication with the transmitter. It will also come up if you have disconnected the pump and are out of transmitter range for any length of time.


Three years, eh? No, I had not realized that. But then, I guess I don’t get out much. :blush:

One other thing to consider is static. I don’t know about your activity level and whether you wear clothes with synthetic fabrics. I had one winter when I had a lot of out of range issues. After getting a new receiver and transmitter, it turned out to be a problem with synthetic athletic clothes rubbing against the transmitter. Here’s a link to my blogpost with the story:

I later found out that others were having the same problem in climates that are not Arizona- dry. In the comment section of this blogpost by a Canadian athlete who lives in a more wet/cold climate, you’ll read that he has lots of problem with static (there’s nothing about it in the main body of the post–just the comments):