Guardian 3 Issues

My 12 year old daughter was recently diagnosed with T1D. I have went from impressed with the Guardian 3 to now wondering what the point of using the Guardian 3 is. Looking for advice from someone that has had a Dexcom G6 and Guardian 3. Should we fight with insurance to get the Dexcom G6? I assume this will be a pain since we just got the Guardian 3 and I am not sure how their returns work. We are on the guardian 3 because her Dr was pushing Medtronic hard. If we change sensors we need to do this before she gets a pump in a few months. I appreciate any opinions and recommendations.

Here is what we have experienced so far. First sensor was placed on abdomen. Accuracy after the first day seemed fairly good and we were impressed. I seen the MARD was better for on the back of arm so we tried that with the next sensor. Accuracy ended up being good but not quite as good as the first sensor. Third sensor is where things started going down hill. On the third sensor it was placed on the abdomen. This was not the same spot as first sensor and she has never taken insulin in the abdomen. This sensor was way off with each calibration. Less than a day into wearing this sensor I wake up to a notification that her sugar is 66. I wake her up prick her finger and its actually at 177. Calibrations are never accepted after this point and we had to try another sensor. The sensor after this one tended to mostly stay lower than her blood sugar test by 10-40mg. Current sensor is wildly inaccurate again.

Hi @JB1001 and welcome to the forum. I’ve only used Dexcom and am on the G6, which I love. There are a number of forum discussions about Guardian, some with comparisons some without - that can give you some reading material to start with while you’re waiting on responses to your post. If I were you I would contact my insurance right away to see if there’s a time limit for making a change, should you decide to do so.
I’m using Dexcom G6 Control IQ with my TSLIM pump and it’s working very well overall. As you may know you can use Dexcom with a smart phone or handheld receiver too.
You might do a search for “compression lows” - that could give you some insight into the difference between her Guardian reading and her fingerstick in the example you shared. I understand that is just one of your issues but it can happen with Dexcom as well, so I thought you would want to knew. Insufficient hydration can affect readings as well.
Wishing you the best on your decision.

Hi @JB1001 welcome to Type One Nation

the trick is how and when you calibrate the guardian. I have had better luck ONLY calibrating guardian when my blood sugar isn’t changing for 1+ hours. This is hard to do because this is often 5 hours after a meal. I took to forcing the calibration to 1st thing in the morning or skipping lunch. total pain.

your insurance will likely let you switch once the transmitters fail.Make the Decom rep find out what the rules are and what your costs are. that’s their job.

some people do not do well with either CGM. Some people are fine with the guardian if they figure out how to properly babysit the calibrations, I have heard the most frequent positive feedback from Dex and then Libre.

If you require a CGM that works with a pump, then Guardian with Medtronic and DEX with t’slim those are not negotiable. There is no absolute requirement unless you HAVE to be on feedback (auto) control.

I’d hate if you go through the trouble of switching and find trouble with the dexcom. I would ask if Dex would do a trial with her to compare directly in order to make up your mind. if dex works then your choice is, IMO, easier…
good luck

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I wanted to seconf what @joe said about letting your rep do the work. While you should check on any deadlines, when it comes to getting approvals and determining insurance coverage, it’s best to leave that to the pros. I’ve tried it myself and sometimes it felt like we were speaking different languages so leave that to them - you’ll save yourself a lot of headaches.

I used the Guardian 3 for 4 years and am now on the Dexcom. I would highly recommend the Dexcom (and the Tandem t:slim pump) mainly because of the accuracy and ease of the Dexcom. You do not have to calibrate it, it is factory calibrated. The new Guardian CGMs are supposed to be factory calibrated so you have fewer calibrations, but fewer is not zero.

If you are having wild inaccuracies with your Guardian CGM, be careful with timing of your calibrations. If your calibrations are off and the first is rejected, you will need to check your manual fingerstick sugar against your ISIG (I think you basically divide the BG by the ISIG (I got this from my pump, but I assume whatever device you have giving you readings from your Guardian CGM will have this info)) I tried to find a website to explain this more clearly, but I wasn’t able to locate it. I would check with your doctor or call Medtronic to help.

As far as insurance you may be able to switch over as the Dexcom is more of a disposable system. The Medtronic system has a transmitter that you reuse for 3-4 years (charging it each use,) whereas the Dexcom transmitter you use for 3 months and then get a new one. It seems more flexible for being able to get on and off of.

I don’t know if that helps at all, but good luck.

Sorry, just another note on the Dexcom. I have nothing but positive things to say about it’s accuracy and ease of use. As to the negatives, many people (myself included) have an allergic reaction to the adhesive used on the insertion site. There are ways around this, depending on the severity of the reaction, but this is an issue I did not have with the Guardian. I would say Dexcom is easier to use, no calibration alerts (which were consistent and annoying on the Guardian), and getting the readouts on my phone gives me a more robust picture of what is going on with my sugar (you can also have this information sent to your phone as a parent so you can see what’s going on with your daughter’s sugars,) but I do have issues with the adhesive (there are other threads on this board about that). As for the Guardian, the calibration alerts were the main problem I had with that CGM and with the Medtronic pump, and the information from the CGM is available but was not as easily accessible (Medtronic may have improved this, but I don’t think it is as robust as the Dexcom system or as easy to use.)

The pump brand will drive which CGM you use so be sure of your pump first! I just switched from Medtronic to tandems tslim and I am so happy that I did! Tandem is giving me much better control. When you use an insulin pump and CGM as a closed loop system, the 2 devices are specific to each other. Tandem uses Dexcom and medtronic uses their own CGM.

If you’re thinking of switching I would do it before you get to the pump. The pump is much more expensive than than the transmitter, and once you get the pump you will most likely stick with it for the duration of the warrantee (4 yrs). I am a new pumper, A little over 2 years using the medtronics. (been diabetic closer to 50 years and with this pump my sugar is higher than it’s been in decades. I didn’t know any better and stuck with it through the warranty period and now I’m stuck for about a year and a half more. With the little over 2 years of using the guardian sensors I have gotten a little better at getting them to last and give better results. A lot ofit seems to be due to better taping and using skin tac wipes when setting them up. The transmitter cost in the hundreds of dollar range while the pumps are in the thousands of dollars so definitely switch before you get the pump. (Medtronics pumps are extremely stressful with many unreasonable alarms)

Everyone thanks for the responses. Compression lows do seem to be an issue for us at night. I didn’t know compression lows were a thing. The accuracy with the current sensor seems to be fairly good most of the time. General readings on the guardian for us are 5-30 below blood glucose when reading are below 180. Not sure how this accuracy compares but seems to be workable. Now thought after looking at the dexcom I am still thinking maybe its the better choice with less finger sticks and better accuracy (maybe?). Once we get a pump it would be a 770 or 780G with guardian if available in US by that time. Or G6 and tandem tslim. The tslim and 780g seem to be close to the same I believe in capability. Seems still stuck on the sensor as a pump working as a closed system is only going to work good if there are good sensor values. I am going to ask about trying the dexcom.