A Nurses Review of the Medtronic Continuous Glucose Monitor (CGM)
Last week I wrote about my love hate relationship with my Medtronic Continuous Glucose Monitor (CGM). This morning I had yet another “bad sensor” alarm and ripped that puppy out of my belly.
I don’t think I’ll be wearing it for a while as my love has truly run dry this week. I had a value in the middle of night 100 points off, so why bother you ask?
My point exactly- that sensor is in the trash!!
Here is an honest and insightful review of our Medtronic CGM’s. My 10 year old daughter and I both have type 1 diabetes and wear CGM’s.
What we like about our Medtronic CGM’s:
- Once inserted the sensor is usually (not all the time) painless and we forget its there
- The size is much smaller than previous gangly sized versions
- It holds a charge really well
- It charges very quickly and the charger is very small/ portable
- With our clear Smith and Nephew opsite tape on top of the sensor it is bomber, not bouncing or moving
- It is sturdy for running, skiing, riding, swimming and all sports we are active with
- When it is accurate it is an amazing tool for trending blood sugars and basal/ bolus adjustments
- We love that it is compatible with our Medtronic pumps and that we don’t have another device to lug around with us, the only thing that is extra is the site
- It is so convenient to look down at your pump and see what your CGM blood sugar reading is- since you are already tethered to it
- We usually don’t use any of the alarms in our family. You can turn them off and use it as a guide rather than an annoying beeping machine (it will beep a lot as referenced because of variability of actual glucose level vs. serous level)
- Finally- you can wear the sensor in a hot bath, hot tub, or swimming pool (This is huge for us as we own a hot tub) It’s also a drag to add any restrictions because of medical devices
What we don’t like about our Medtronic CGM’s:
- We dislike all of the errors- cal errors, bad sensors and misbehaving sensors in general
- There’s not much to like about the inserter- it is not user friendly, it has an exposed needle and a loud popping sound (not popular with kids)
- Numbers on the CGM can vary wildly, that is why I don’t like engaging the alarms
- This thing can make you an anxious mess if you look at it all the time- watching a low blood sugar with double arrows down will make anyone more nervous then they already are with a low
- It would be nice not to have “twins or tandems”, double sites- one for insulin and one for monitoring (granted this is a standard in CGM’s, having the measuring device away from the insulin source- for obvious reasons)
- Because this is a measure of serous fluid, I find it most useful for trending and adjustments, and also for avoiding surprise highs and lows. I never look at my pump and think- wow my blood sugar is excellent or high without checking my blood glucose first
- I find that across the board there is great variability between sensors and the accuracy of their results.
You are spot on! I just started the Medtronic CGM and went through 3 sensors in 3 days with results way off! How did this get approved by the FDA? I switched from a Dexcom (love it!) CGM and will go back to Dexcom. The insterter is self-contained (almost error free), it lasts for 7 days, and results at most are 10-20 points off. Much better product.
I have used Medtronic CGM for 5 years now. I am rarely without it. First, despite the “official” 3 day life of the sensor, they can be used for up to 7 days, just restart on day 3 and 6. In my experience, day 1 and day 7 are the least reliable for glucose readings. In fact, I found this post because I am having some “sensor error” alarms (multiple) today after inserting a new one. On days 2-6 the values are fairly accurate except, as Medtronic says, during rapidly rising or falling glucose levels. Remember, the glucose in the interstitial tissue is behind the glucose in your blood and in rapidly rising or falling glucose it takes a while to catch up. Day 1 can be off because the sensor is adjusting to my body and day 7 is often off because it is at the end of its useful life. As for the high and low glucose alarms especially on days 2-6, I have found them quite useful for taking corrective action especially at night. For the most part, I double check the readings by checking my blood, but that should always be SOP. Sensors and CGM’s are not perfect but they are a useful tool for management. Anyway, that is my take.
I have had the CGM for a few years. For the most part I like it. I did have some cal errors and bad sensor issues. What I have found is make sure when you calibrate with a glucose test, make sure you have not just eaten or you blood sugar is on the rise. I have used expired sensors with no trouble. Physician hubby didnt think there would be any reason a sensor would expire. He only thought that that is the length that sterility could be promised. Most problems seem to be user error.
Vikki, thank you for your input. My daughter and I use the Dexcom system now and the issues you mention with calibration don’t happen with the Dex. They actually recommend that you calibrate during times of change (convenient). We never have sensors expire because we love our system so much and the accuracy is outstanding that we run out of product every 3 months (a good problem). There is another gadget (the receiver) which is a bit cumbersome but the correct results are worth it. The next generation will be cell phone compatible too. Here is my full review of the Dexcom G4 http://www.shesugar.org/insulin-pumps-and-cgms/dexcom-g4-platinum-continuous-glucose-monitor-nurses-review-type-1-diabetes/
I must say that user error is only a portion of the problems that exist with the Medtronic CGM unfortunately. Their next model is coming out soon in the U.S. with many technical improvements so hopefully customers will be happier with their product. Best! Jewels
Hi, thank you for your reviews of the medtronic CGM system. I’ve been diabetic for nearly 16 years, and pumping for ten. Recently I’ve been thinking about trying out the CGM because for some reason, highs and lows don’t seem to wake me up anymore during the night. I have a few questions, if you’d be willing to answer. I like being able to ask other diabetics instead of just doctors and sales reps. How much bigger is the CGM needle than a regular set needle? ‘Right now I’m using the silhouette because I hate spring-loaded things with a passion (sometimes I can do the Mios, but I prefer manual insertion). Would it be possible to insert it manually? I’ve been reading other reviews, and now I’m actually considering a Dexcom, even though it wouldn’t have the convenience the Medtronic does.
Courtney,
My daughter and I both have been using a Dexcom for the past year with great success. Here is my review of the G4, their most recent model. http://www.shesugar.org/insulin-pumps-and-cgms/dexcom-g4-platinum-continuous-glucose-monitor-nurses-review-type-1-diabetes/ It is a self insertion system which sounds like what you are most comfortable using. Best! Jewels
I have the Medtronic CGM and it seems to work half the time: half really well and the other half is frustrating. My sensor seems to have ‘weak signal’ problems all the time. I am always trying to stuff my pump into my clothing as close to the sensor as possible, and sometimes this works, but only for a little while. I found this website because the sensor I inserted about 24 hrs ago has been nothing but pure frustration (weak signal!) so I was searching for forums/reviews. I have called the manufacturer and followed their tips, but haven’t seen huge improvements. In any case, there is no way that I can follow the advice to wear this in my abdomen all the time because the insertion needle hurts. A lot. I am going to look into the Dexcom sensor–hopefully insurance will pick it up. As for the Medtronic CGM, some days it seems like the number it reads is only accurate in telling me what my blood sugar is not.
I have had similar issues with the Medtronic cgm. I wanted one for bicycling and seasonal basal calibration. when I have my pump in my jersey pocket, I have to wear it as close as possible to the transmitter which leaves the pump hanging to the side a little more than I would like which could result in the pump getting damaged if I crash. riding I loose connection about 30% of the time, probably because I am passing by something that creates enough interference that the transmitter cannot break through.
the main problem, I think, is the fact that minimed sold out to Medtronic. I work in the manufacturing sector so I am fully aware of what results. “cost savings measures” can result in less than reliable products. I have had trouble, with my batch of cgm sensors that I bought in 2013, while installing. the insertion needle proves to be difficult to remove which could be the cause of some of my failed sensors. perhaps some of the reactive chemicals are stripped away with the needle removal or the metal of the sensor itself gets bent enough to create resistance that would cause erroneous readings. just guessing.
the new design of the infusion sets with the integrated tapes are difficult to install without the tape bunching up. didn’t have that with the 317 infusion sets which they stopped making recently.
if I could afford to switch I would, at least for the cgm
I have used the Medtronic CGM for 8 months and am shocked at how inaccurate it is.
Today the meter read 79 but when I did a finger stick my glucose was 32. The scary thing is that I was just driving before I did a finger stick to verify the number. If I am within 1 hr of calibrating the reading is fairly accurate but outside of that 1 hr. window it has a huge range of being off the mark. Have not noticed any difference based on the number of days the sensor has been worn.
You are so correct. Mine keeps suspending when it shows a low sugar yet when I test , there is such a variance in numbers. Ex. Shut down showing a glucose of 47 after testing , I am 112. This is bad for anyone.
I am going to call Medtronic again
I am on the latest Medtronic CGM, I have to agree with the majority of comments, that Medtronic’s has some work to do in getting better accuracy with CGM.
First of all the CGM lasts reliably about 3 days not 6, therefore the bean counting pharmacist thinks you are overdosing when you use twice as many as the Medtronic spec tells them.
Be prepared for many false highs and low alarms, therefore either not using the alarm feature or setting the values way high or low.
Inserting the set is a complicated operation when you are doing it to yourself, particularly placing the sealing tape over and around the sensor properly securing and protecting it.. It is apparent the design team at Medtronic’s has never tried to use the product on themselves.
I tried the CGM a few years ago (medtronic) and the readings were way off. It was frustrating, especially with all the alarms. The calibration timelines are at minimal, inconvenient. It’s been a few years and I am about to upgrade to their new closed loop system, so I thought I would try a CGM today to get back in the swing. I’m already frustrated and about in tears because of the inconvenience of the whole system. The memories are all coming back…inconvenient calibration times, alarms going off, losing sleep because of the alarm, and the itchiness of the site. Doctors treat me like I’m crazy for not using the CGM and having blood sugars in check, they don’t get it.
Brian,
Stay with it – my experience keeps improving. The Guardian 3 Sensor has been really reliable once I’ve gotten into the swing of things.
Best,
Jewels