670G New Sensor Nightmares!

Hi, all! Brand new here. Trying to find reasons to not throw my 670G into traffic! Looking for anyone with similar issues…

Medtronic pump user for nearly 20 years, 670G/CGM for only the last two. Every week (if they last that long) the first day of a new sensor is an absolute nightmare! Insert >> 2-hour warm-up >> calibrate >> 3-hour window >> maybe just close enough to calibrate >> 6-hour window >> SG 100-150+ points different! So, I spend several hours of hourly calibrate alarms trying to get my BG down close enough to that last SG to calibrate. If my BG is 150, then the SG will say 40 and tell me I’m dying! Or, I force my BG up to 275 so the SG goal is a comfortable 150. It takes about 18 hours to finally hit the magic 12-hour window, then I’m good for hopefully six more days. (Usually.) Every. Single. Sensor. Medtronic told me it’s scar tissue, but then how does it work after that first day of hell?!? Many sleepless nights trying to calibrate (tonight!), tears of frustration, and lots of swearing!

I insert in my upper abdomen, and my transmitter is from May 2019, so should be the newer/better one(?). (Same issues with prior transmitter.) Really don’t want to try other sites because the majority of my problems are on the first day only. (For the most part.) Anyone else feel my sensor pain???

Hi @StorybookGirl welcome to TypeOneNation. I think there are a lot of us who have had issues with the Medtronic sensors. I didn’t upgrade my pump due to high deductible costs, and because I was waiting on feedback and apparently the Medtronic sensors haven’t improved much.

I was wondering, it sounds like you have a system, but still I was concerned that you drive your actual blood sugar to a target and then calibrate. I am sure it works but I have to ask, why don’t you just lie to your sensor? I have had decent luck with holding my blood sugar steady and then calibrating closer (in 50 mg/dl steps) to my actual blood sugar. On times when the sensor has been way off, I eat, wait 4 hours for a rock steady bs then calibrate again with another lie and by the third I’ve been able to get the sensor right in there. Anyway just a suggestion from a battle worn 3 generation guardian hater. I am not sure I am going Medtronic next time but I am not a tslim fan either. Cheers good luck :four_leaf_clover:

@StorybookGirl Hi Kris and welcome to the JDRF TypeOneNation forum! I’ve heard that the 670G is a good piece of hardware, so don’'t crush that - the Guardian sensors, on the other hand, do not work well for many people.

Like you, I was long-term user of MiniMed pumps but in the last two years I’ve migrated to the DexCom G5 / G6 sensors with a Tandem t-Slim pump - excellent results. Around 2009 I decided that the Medtronic sensors were not for me, so I began to rely / replace the sensors with several finger-sticks per day. Unlike @Joe, I wasn’t clever enough to figure out how to lie when doing calibrations - although, I did learn a bit about that [mostly delaying calibration] with my G5 sensor.

Good luck on whatever you try.

Hi, Joe. Thanks for the response! Well, it has occurred to me to lie just to get it over with, but I don’t think I’m that clever! You seem to have it down, though… interesting idea. I’m surprised it finally catches up. Then again, I’m finding on this forum and others that the real takeaway about the Guardian sensors and the 670G is that they have to be tricked and manipulated to get them to work! Shocking how the company that developed the closed-loop system can’t design a sensor that’s worth a darn, which makes the amazing pump borderline useless. I’m so frustrated! But thanks for the tips… I may just give it a try.

Hi, Dennis. Thanks for your reply! As I mentioned above, it is so frustrating that the Guardian sensors are not on par with the 670G pump. As a longtime happy Medtronic user, I automatically went to the latest Medtronic pump when it was time to get a new one two years ago. I purposely waited several years before going on a CGM to give them time to “perfect” them - guess I didn’t wait long enough. I can’t believe the level of anxiety caused by these sensor failures! Next time I know to research other options - a couple years away, so hopefully other companies will catch up to the closed loop, which, in theory, is so attractive. The sensor I started three days ago already failed - 4th one from the same lot, which has happened to me with two different lots in the past couple of months. Where’s quality control? So, another sleepless night for me. First calibration alert: SG 84, BG 187. Anyway, sorry, I’m just venting now… but hopefully someone will read my cautionary tale and do their own research!

I know what you are saying, Kris @StorybookGirl, when you say you were inclined to stay with MiniMed/Medtronic because of your previous experience. That is how I felt too, and after meeting personally with a couple of Medtronic educators/representatives, I found myself highly impressed with possibilities for good management. I also met with Tandem, Dexcom, Insulet, etc. representatives.

It was when I held the Tandem t-Slim in my hands, was able to clearly read the screen with my weak eyes in sunlight and and dim light, and having spent hours witha DexCom representative at a JDRF function, that I chose my current Tandem/DexCom AIDs. The fact that both DexCom, and then Tandem, worked everything out with United Health and Medicare was a real bonus. Medicare would cover the 670G, possibly, but not the Guardian [unreliable] sensors.

Attending JDRF Meetings has introduced me to representatives of ALL diabetes “tool” manufacturers.

With all the posts I read about Medtronic sensor issues I have to wonder how they keep going. Medical devices have to meet quality control standards for accuracy and reliability among other things; and it seems they are lacking both.

@StorybookGirl, Medtronic is aware of the issue & are sending new transmitters out that don’t do that crazy “looping”. I received my new sensor several months ago and the issue is gone!

Hi Kris,

Absolutely feel your sensor pain! I’ve had the 670G for about a year but had been an Animas user since 2000. In the beginning few months of the 670G, I would frequently want to throw it in a large body of water for the reasons you mention. But over the past few months, I think I found a way to work through the first day sensor issues.

I will disagree with others on lying to your pump - it is (in theory) supposed to learn from your BG to adjust the Auto Mode, so lying to it will only yield bad data. I try to insert my sensor as early in the morning as possible (to allow for hiccups in the Auto Mode warm up process) but otherwise do everything as they describe. The hang up I get is usually between the 2nd and 3rd calibration of the day, where I usually get different numbers between BG and SG - and yes, mine are often as extreme as yours (BG being 150 but SG says sub-40). When this happens, I calibrate (even though it’s wrong) because this helps the pump get it’s bearing. So it will ask for an immediate BG due to the discrepancy, but I ignore that for awhile and when I do this, I usually see the SG number rapidly adjust/get caught up even though the shield is grey. I give it some time to get more aligned then will enter my BG. For the past few months, this has been working for me but absolutely agree this is very frustrating especially when other systems don’t have these kinks.

I would also agree that the tech support at Medtronic is spotty at best. My sensors only used to last four days and their answer was my body chemistry must not agree with the sensor but now my sensors last the full seven days. I try to give them the benefit of the doubt that we’re working with state of the art tech and that our struggles will only make it better for future generations of diabetics.

Hi, I have been on the 670g and the new sensors for three years. I too thought about tossing it for the first three months. However, I persisted. Read a lot. Joined the Medtronic 670g group on FB. I wear my sensor on the back of my arm, above my elbow. I have also worn it on my thigh. Both sites are way more comfortable than my abdomen and have much more consistent results. I am on automode except when the first day. My lows are far more infrequent than on previous sensors and -my highs are rare. I now run time in range around 90-92% (70-180 is my range) and my A1c’s are usually around 6.5. I encourage you to keep at it. The system does work.