Xdrip adventure to date

Tips, Tech & Gear
1

I’ve been testing the xdrip app for about a week now with a Tandem tslim pump and a Dexcom G6. The pump is acting as the receiver and I had the G6 app installed on an Android Galaxy s8+. I just wanted to share my recent experience in the hopes that it can help others.

I’ve removed the G6 app and installed xdrip 4 different times and always had to revert to the G6 apps due to issues. I was using xdrip on Sunday when I went out to dinner with family. My blood sugars for the night before were flatline between 110-120 (unusual). I checked my blood sugar with a meter Sunday morning and got a reading of 154 (pump and xdrip said 114). I calibrated using the pump but neither device changed. Like they never saw the calibration.

I calibrated an hour later and meter said 177 but pump and phone still reading between 110-120. I uninstalled xdrip and after 3 hours, the pump finally started to show a rise after I ate. I reinstalled xdrip Sunday night (using the nightly build) and everything seems fine so went to bed.

Monday morning is a repeat of Sunday morning. Pump and xdrip show flatline of 110-120 over the night but meter reading is in the 170’s again. I calibrated using pump and the glucose readings on the pump updated but xdrip did not. Xdrip also was giving me an insufficient calibration error and stopped displaying readings. In the xdrip logs, I was also getting unknown data from transmitter warnings.

I then did the initial dual calibrations inside xdrip. Not only didn’t the warnings inside xdrip go away but my pump starting giving me bad calibration warnings. I tried 5 calibrations using the pump and finally called Tandem. I did not mention xdrip, obviously.

They said that after 3 bad calibrations, I should have just called and asked for a new sensor as they were sure it was bad. I had planned on just starting a new sensor when I got home from work, afraid that the transmitter might be ruined. But considering I didn’t have anything to lose, I tried this instead.

  1. Uninstalled xdrip and put Dexcom G6 app back on phone. The G6 app started and immediately gave me the same calibration errors that I was getting from the pump.
  2. Using test strips, I was able to successfully remove the transmitter from the sensor.
  3. From the pump, I stopped the sensor.
  4. I left the transmitter out for over 1/2 hour. I did not try to forget the transmitter on the phone or the pump. Just let it sit on the desk for awhile.
  5. I finally put the transmitter back in and from the pump started a new sensor. I used the original code from the sensor and waited for the 2 hour warm up period.
  6. When the warm up period ended, pump and phone both read 288 but meter said 208. I treated for the high reading but did not calibrate because my blood sugars were obviously high.
  7. When I woke up Tuesday morning, pump, phone, and meter readings were all in sync. I have calibrated twice since then just to check for errors but none have occured.

Sensor readings are still corresponding with meter readings. The sensor was 4 days old and did reset to 0 so I picked up an extra 4 days. I like the interface and features of xdrip but am uncertain as if I will reinstall. It turned out ok this time when Tandem sending me another sensor. But if xdrip had fried the transmitter, I would have been out of action because I could not order any new ones until January 18th.

Hope this helps some of you who have been going through similar issues. Always open to comments and suggestions on anything related. For information purposes, the transmitter is an 81 series.

Merry Christmas everyone.

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2

Can you provide details on xdrip settings?

Were you using Native checked or not checked ?
If checked, xDrip should basically show readings determined by dexcom transmitter, and be identical to receiver/tslim display.

If not checked, xDrip starts with raw transmitter data and does own bg calculation.

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That was the confusing part for me as well. I did have Native checked and yet the readings were not identical before the calibration error. It almost seemed as if xdrip wasn’t getting data that it could understand from the transmitter. Please keep in mind that I was using the most reason nightly build of xdrip at the time. I should have known better then to use a possible unstable version.

4

I’m using 2019.05.18 stable version, but plan to update to newer 2019.10.27 stable version.

I know many use setting to get every new build.

5

I’m ready to give it a try again but will use the most stable version and stay away from the nightly builds. I will just use it in place of the Dexcom G6 app and not try to do anything with the sensor or transmitter for a few days. The tslim and the G6 app have been showing good readings for the past 2 days so if I start running into problems right away, I will know it is xdrip related.

6

I would highly recommend this. I’ve never known even a software developer to actually use someone else’s latest version on their own system on a regular basis, indeed, sometimes I’ve suspected that some software developers don’t even use their own latest version. (BTW I always did.)

My understanding of the G6 is that pretty much everything happens within the transmitter. I’ve watched xDrip+ and my Dexcom receiver closely over the past few weeks and the latest reading is always identical.

I don’t think it is possible to turn off the “native algorithm” check box if the “G6 support” check box is set. The “source wizard” turns it on if you select a G6 as the data source and so does a reboot of the phone. In the latter case there is a moment when xDrip+ declares it needs calibrations, but this disappears within 30s of the reboot (on my phone).

The “initial calibration” menu entry and, indeed, all calibration menu entries seem to have disappeared, at least initially, in the 1027 build. The bug where a downloaded meter reading prompts to ask if you want to use it for calibration is still present, so I can see that since calibrations have been disabled everywhere else if you make the mistake of accepting this dialog bad things might happen. Indeed, a downloaded meter reading seems to cause “initial calibration” to reappear.

My belief is that xDrip+ will send calibrations to the transmitter and, therefore, if it does so, I can quite understand that this may mess up the transmitter state in a way detectable by either the pump or the Dexcom app (or, indeed, the receiver, but that has more ancient software.)

Prior to 1027 I do know that 0518 did ask for calibration readings if the sensor code was not entered. That would seem to be a bug too; so far as I can see that is only a reasonable thing to do if the transmitter does not already have the sensor code.

7

Thank you so much for your input. Because I’m using a G6, I always enter the code. Also, I never use the Dexcom receiver as my tslim pump replaces it.

It appears that you are saying that I should NEVER enter a calibration in xdrip, regardless of if it asks for it or not. I will assume that this is what you’re saying and will only calibrate from the tslim from now on. Please correct me if this is wrong.

I have never used any version but the 1027 other than the one time I tried the nightly update. And the 1027 version did ask for calibrations even though I had entered the code.

8

Ok. So here’s an update. I uninstalled the G6 app from my phone and installed the 1027 version of xdrip on Thursday morning. I’ve been extremely careful to only use xdrip to monitor. No calibrations from xdrip. Only from my tslim pump. Because I’m skeptical about this current sensor, I have calibrated from my tslim several times. Both the tslim and xdrip accepted the calibrations and adjusted accordingly. But the meter readings were all quite close to the G6 value.

When I got home from work tonight, my new One Touch Verio Flex had arrived. I had been using an older One Touch Ultra and wanted to make sure I had an up to date meter to carry out these experiments.

My first meter reading was 156 while the G6 was showing 112. I calibrated using the tslim pump which said that it accepted the calibration. The readings on the pump went up to 133 but the readings on xdrip didn’t change at all and an insufficient calibration error showed up.

A few minutes later, my pump asked me for a new calibration, which I entered as 112. Obviously by blood sugar had been falling at the time of the initial calibration. I had to wait around 20 minutes but finally the insufficient calibration on xdrip went away and xdrip and my tslim started reading the same again.

As before, looking forward to any comments or suggestions. Still undecided about if I want to continue using xdrip.

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Hi @churcr

I used the Verio for a while. I found it reads higher than my other meters and when I take multiple readings at the same time (from the same drop of blood) they can be wildly different. I was using the G4 at the time but this lead to all sorts of issues with trying to get a good calibration. One way to look at this is you are giving the calibration algorithm a lot of different BG readings for the same measurement from the g6 sensor. This is confusing.

I switched to the Countour Next One meter, which gives very repeatable readings and a lot of the calibration issues went away.

@jbowler also mentioed that if you go under **settings > G5/G6 Debug Settings ** and see **Native Algorithm ** checked all the caibration calacultions are done on the G6 tranmitter and all devices should read the same. Also you should be seeing similar error or warning messages on the devices so xdrip and the pump should be telling you to calibrate around the same time as the status comes from the tranmitter.

Good luck with xdrip. I have been using it for a long time for me and my son so I am used to the quirks.

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10

I had the multiple One Touch meters and found that when I compared them I got different readings, sometimes very different. That was incredibly frustrating as I already distrusted my CGM. I researched accuracy and found the Contour Next was published to be the most accurate. I switched and agree. I have never had a meter more accurate than either the Contour Next One and Contour Next Link. The kink connects to my pump. The One connects to Xdrip. But either one is great.

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11

Well, after doing some research, it would appear that Countour Next is considered to be the most accurate. I actually have two Countour Next Link meters from when I was using a Medtronic pump. Medtronic originally used the One Touch Ultra link and then switched to the Countour Next Link. Both of these meters connected to the pump through bluetooth.

The problem was that I hated the case layout and lancing device for the Countour so I just stuck with the One Touch. I’ll consider going back to the Countour but might have to wait because my insurance just paid for the Verio test strips.

To continue my story, I got up this morning and pump and xdrip were in alignment and showed relatively flat line through the night at around 130. At 10:30 am, xdrip gave me warning about predicted low. The reading was 68 with double down arrow. The pump had no reading at all.

I did some manual testing and here are the results of all readings:
xdrip 68
tslim no reading
Verio Flex 173
Verio IQ 163
One Touch Ultra Link 150

Both the pump and xdrip gave sensor errors although it took the pump longer before it showed the error. I figured that the sensor was indeed bad and maybe has been all along since before I restarted it. FYI, the sensor is 9 days 8 hours old from the original insertion but is only showing 4 days 15 hours from the restart that I did.

I decided that is was time to change out the sensor but was doing some research on meter accuracy and at 11:15 the sensor came back online with a reading of 118. The Verio Flex gives me 148. A calibration gives me errors on both devices so I’m going to start a new sensor.

@RCA221 Can you please tell me what pump you are using and if you are using a Dexcom G6. @Aaron When you do calibrations do you do them from your pump/Dexcom receiver or from xdrip on your phone? @jbowler made it appear that it is not a good thing to calibrate from xdrip.

12

I too hate the contour lancing device so I use the one touch delica lancing thing. It is small so I can fit the contour next one, an insulin pen and the lancing device in the case. It is tight but it all fits.

I only use xdrip so I just use my phone for calibration.

For me I never really calibrate the G6. It generally is spot on with the contour next one.

For my son, we have to calibrate because it is usually off. I find calibration can introduce errors so it is best to calibrate with a flat line.

I use a pump (omnipod) and I regularly flat line so calibrating with a flatline is no problem for me. My son is 4 and on mdi so there is a huge randomness on blood sugars that I cannot account for. It is definitely harder to calibrate. I usually use patience but my wife will just calbirate with every bg test that is out and it works ok eventually.

13

I concur the case layout for the contour next is undesirable. But I’ve gotten used to it. Right now I’m using the g5 not the G6. My pump is the Medtronic 723 paradigm pump. At some point I’ll move to the G6 and probably the t slim pump.

14

I use the Contour Next One and find it to give readings which match a stable, uncalibrated, G6. The Next One gives readings which seem to be 3-5 minutes in advance of the G6 and xDrip+ seems to record them as maybe 10 minutes in advance.

For example I just did a Counter Next One test at 11:48AM, the test gave a reading of 123mg/dl while xDrip+ has a reading from the G6 of 170mg/dl at 11:47AM (the same as the Dexcom receiver). On the main page xDrip+ graph the 170 reading is in about the right place but the Contour Next One reading is placed at around 11:58AM on the graph even though clicking on it shows it was recorded at 11:48AM. Two readings later and a reading of 178mg/dl recorded at 11:57AM lines up on the graph with the Contour reading.

I don’t calibrate because when I did it did not seem to help overall activity. Someone (@Eric?) suggested not calibrating until after the first restart and that it as important to do so then but my experience is that I haven’t seen any worse errors after the restart, days 9-15 or whenever the sensor errors start.

Around 5% of sensors “fail” before 10 days according to Dexcom, a sensor error from the transmitter is a failure even though the transmitter can apparently recover. My sensors tend to start having sensor errors before 15 days, i.e. most of them are failing then, which is broadly consistent with Dexcom’s failure rate.

15

I will have to look into getting the Contour Next One soon. Until then, I have managed to get my One Touch Verio Flex to connect to Xdrip and upload the readings. I have the “Use meter readings to calibrate” setting turned off. My last meter reading was 101 at 4:48 pm and it wasn’t until 5:30 pm that xdrip and my pump matched this reading. But the meter readings were taken before I was able to connect the meter to the phone and xdrip.

I will keep it in mind that sensor errors are going to happen and accept that this means the sensor is bad. I just hate to loose a sensor because my insurance is very strict about time. If I ordered a months supply of sensors on 11/15/19, they will not approve another months supply until 12/15/19. No exceptions. And that doesn’t make any room for errors.

Although I did manage to restart this sensor after 4 days, I now believe that it was probably bad before the restart. And when I stopped it today, it hadn’t quite reached the 10 day cutoff since the initial insertion. Although I didn’t gain anything on this sensor, Tandem did send me a replacement so I’m 10 days ahead of my insurance company.

When I am able to order again in January, I will have to order sensors and transmitters. I use Solara as a supplier and have nothing but nightmares when it comes to getting new transmitters. The last time I ordered in July, they said that the RX for the sensors was ok but the RX for the transmitters was expired. Even though my doctor had written the RX for both items for the same amount of time. It took over 2 weeks to get it straightened out so I was without sensors for around 10 days. If that happens again, I just used up my 10 days of security.

One final question. You say that you were advised not to calibrate a G6 until after the first restart. What I want to know is it ok to calibrate from xdrip on the phone or is this a definite ‘NO’

16

Thanks @Aaron I also have several delica lancing devices and use them. But they don’t fit in the Contour built in pocket. I rarely ever calibrated the G6 until I started using xdrip. Plus it is becoming more apparent that the sensor I was using was probably bad all along.

I used to use the Medtronic pump with their sensors and I finally gave up on it. Medtronic sensor required daily calibrations plus the readings only seemed to be good when my blood sugar was stable and in range. If it went high or low, the Medtronic sensors became worthless.

I’ve heard about the Omnipod and couldn’t use it because of the small reservoir size. I have a 2 to 1 carb to insulin ratio. Even with a 300 unit reservoir, I have to change my infusion sets every 24 to 36 hours. Sometimes I will refill the reservoir and use the same infusion set but it usually starts leaking at the site before it is empty.

Starting in January, my insurance will start covering Humalog U200 and hopefully I will be able to get twice the life out of an infusion set. Thanks for your input.

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17

I never used the G5. When I got my initial order for the tslim, I chose the G6 even though the tslim wouldn’t be able to link with it for another 6 months. I liked the idea of not having to calibrate twice a day.

I was using a Medtronic pump before but chose Tandem because it seemed to be using more modern technology and I hated the Medtronic Sensors. Couldn’t depend on them at all.

Of course the tslim has its own set of issues. But I suppose any technology like this will!

18

Positive update! I started a new G6 sensor with code (from my tslim pump). Both the tslim and xdrip showed new sensor warm up.

After the warm up time, both the tslim and xdrip showed the same reading and neither asked for any type of calibration. I used my One Touch Verio Flex and got a similar but lower reading then the G6. I did not calibrate and obviously by glucose was falling at the time of the test because within a half hour, the G6 was matching the meter readings. I was even able to connect the Verio to xdrip with limited headaches.

The only possible issue I’m seeing is that xdrip seems to be holding onto the calibration code of my previous sensor. When I go into system status on xdrip it shows Sensor Status: ok 7.9 hours but Calibration code shows the code from the previous sensor and not the code for the new sensor I inserted today. Because everything seems to be tracking on both devices and appears to correspond with meter readings, I’m going to ignore this for now.

The other issue is that xdrip direction errors don’t line up with the tslim. Right now my tslim shows a reading of 114 with a horizontal arrow. xdrip was showing 114 with an up arrow but as I was writing this, it changed to a horizontal arrow. I think that it takes my phone a little while to catch up with my pump.

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19

If you have a sensor error before 10 days then Dexcom will, I believe, replace it. Sensor errors come from the transmitter, it really doesn’t matter what receives those errors. The Dexcom replacement happens outside the insurance loop and when I first started on the G6 (so I didn’t have a stash) the Dexcom replacements I got pretty much bootstrapped the process so that I did have a stash.

I had endless problems getting timely supplies as DME, EdgePark in my case, not Solara. My wife spent a considerable number of hours ringing round between my insurer (moda) and EdgePark trying to get the supplies I needed. I never imagined that a bureaucracy could out-■■■■ her [square dots courtesty of fud, they don’t like the colloquialism for excrement], but they did. It is a debilitating pointless exercise in managed homicide, but it works; we die.

This is why I prefer obtaining Omnipods and CGMs as a prescription benefit; it is still brown stuff, but we (my wife and I) can make it work.

It seems that calibrations with the recent (8G, 8H) transmitters can be rejected. There should not be any harm in doing it, but why? So far as I am concerned if the G6 is giving a consistent set of results I only care about accuracy in the BG range 80-100mg/dl, outside that range it is ‘high’ or ‘low’, which is fine. I’ve never had a G6 fail because I calibrated, but I’ve never got any advantage from calibrating so it has become a ‘no’ for me.

20

Yea, I did get the sensor replaced but not by Descom. I have to go through Tandem because they consider it part of there system. So I am one up on sensors but not transmitters. If I fry the transmitter while trying to extend it, I’m out of luck until the middle of January.

I got so angry with Solara earlier this year that I checked into using EdgePark and was almost ready to make the switch. That was until I did the math and found that they were charging anywhere from 50-150 percent more, depending on the item.

I now that my insurance company has a participating saving thing and max allowed amount that Solara has to abide by. It’s possible that EdgePark prices were not including this yet. But when I tried to talk to a rep about it, he simply told me that it was what it is and if I could get the supplies cheaper somewhere else then I should do it.

I get my insulin through a prescription benefit but to the best of my knowledge don’t have this option with pump supplies and CGM’s. I believe that the OmniPod is a self contained one-time device that I can’t use because of the huge amount of daily insulin I take. That’s why I use the Tandem pump which requires monthly reservoirs and infusion sets. I can’t even get and RX for test strips at my local pharmacy because my insurance company considers them to be DME.

If you consider 100 mg/dl high then you are lucky to have such tight control. I can never hold levels like that. I rarely calibrate the G6 but started doing it when experimenting with xdrip because everything was acting wrong with my sensor. Now I understand that the sensor was bad from the start and xdrip was not to fault.