So, after avoiding a cgm for years due to “fear of adhesives rashes”, my endo gave me a sample libre 3 about 3 months ago, and I loved it and had no reaction to the adhesive…yay! Took the past 2.5 months to get all the paperwork straightened out, but finally got my first shipment yesterday, and I have some questions.
I’ll be going ocean swimming next week. Do I need to do something extra so the sensor doesn’t come off early due to salt water exposure?
When I had the sample on, I tested several random times to see how close the numbers were between the Libre 3 and my Countour Plus monitor, and the were always less than 5 apart. The sensor I’m using now is always 10 to 15 points higher than the Contour. Is this normal?
I was absolutely unable to use the first 2 sensors I tried from this shipment as I couldn’t twist them open no matter how hard I tried. I called Abbott and they’re sending me replacements for those two, but I’m wondering if this whole batch could be off? I checked the lot numbers and they are not the lots that were recalled.
Since I’m a total noobie with CGMs, I’m not sure how much variance is to be expected.
Hello Ruth, great to hear you get to use a CGM! I hope it makes as big a difference for you as it did for me. I’m going to tag @Marie20 because I think she swims with a Libre and can give you specifics. I’ve got some general info for you.
The trick to keeping a CGM stuck to you even after the adhesive has let go because its been underwater for more than roughly 30 minutes is to keep the CGM and adhesive patch pressed against the skin. If the patch and the skin are in contact while everything dries the adhesive will bond again. Tight sleeves can do this but get tricky to remove. The common solution is a big sticky patch over the sensor to hold everything in place. I prefer two wraps of 3M Corban because it sticks to itself instead of me.
Your doc or CDE will go over how to interpret CGM values at your next appointment. Are you good with statistics? If so you can get a head start with the info in the back of the manual starting at page 200. If stats aren’t your thing think of the CGM number as an estimate of your BG. No big deal if an an estimate doesn’t match a measurement right?
I have yet to meet a pickle jar I can’t open but I did have an original libre that I had to use two pairs of slip joint pliers to open. Strap wrenches or belts will also work. Don’t expect the problem to affect entire lots of sensors, it is just a bad design.
Two additional tips for all new CGM users: 1. Keep the sensor dry and in place for the first 12-24 hours after application to increase the chance it stays stuck for the next two weeks. 2. It took me over a year to get really good at keeping a sensor stuck and knowing what the CGM was telling me. Do not underestimate the learning curve and the patience and persistence required to learn how to use a CGM effectively.
Me too, pickle jars! I can open the tightest of jars, but darned if I could open those two sensors. Luckily the third one opened normally.
And thanks for the tips. I’m trying to figure out what would work at the beach - don’t really want to buy another product, and don’t know how I’d wrap anything sticky without getting sand under it. Maybe just dry and hold a towel against it for 5-10 minutes?
I’m not good at all with statistics, but I’m not sure I need to be. My only question on the readings is that they seem to be much higher on the sensor than what I’m getting from the Countour test strips. I’ve been counting carbs and have been on a pump for nearly 22 years, so I’m pretty good at understanding my numbers. And since I’m about to turn 78, I don’t think I need (and my endo doesn’t recommend at my age) super tight control. If my A1c is 6.5 or under at this late state, I’m happy.
A few years back I was consistently getting 5.5 to 5.8, but that came with a lot of lows, and those lows are way more dangerous at my age than they used to be.
Ruth-
I swim in the ocean almost every day with my Dexcom G7 Cgm. And did so with the G6 years ago.
First, I also have skin rashes from the adhesive. So the best thing I found was a product called —skin TAC. It comes like an alcohol swab and you swab down the skin area where you’re putting your CGM and I also use the Omni pod insulin pump and I swab the skin area before inserting the Omnipod . It is a skin buffer.
Then always use the enclosed adhesive overlay. And you can contact Dexcom to send you more for free. You must contact Dexcom in your region area customer service number to get a monthly supply sent to u free
Then you buy athletic tape. It’s not really tape. It’s a cloth like bandage that comes in a roll. You can ask a pool, lifeguard or an ocean Lifeguard about it because it is included in every first aid kit.
You can buy at your local pharmacy but it is best to buy on Amazon because you can get 25 rolls in one box for $25.
If you swim often, you wrap it twice around your upper arm and it is self sticking. Much like an ace bandage but it has one sticky side and one cloth side. It is temporary. You take it off after you swim. Also I have found.
Wear a rash guard shirt with long sleeves. Google search what these are. Wear the long sleeved fits tightly on your arms and secures your CGM while you’re in ocean, water or swimming laps in a pool, and it is very good as a sunblock to protect your skin.
My experience with the Dexcom G6, as opposed to the Libre, is that water doesn’t much matter. I’ve scuba dived with the G6 with no issues and I swim pretty much every day at this time of year with no problems (both G6 and now G7).
What does matter is sweating, something which typically doesn’t happen under water. Not as in a sauna (which I also do whenever possible) but combined with exercise or tight clothing the sweat does manage to loosen the adhesive and the movement, or clothing, does the rest.
I avoid clothes, they’re the worst, but exercise alone is still a problem; sweating and movement so no problem in a sauna (no clothes no movement, or not much.)
You probably where a rash guard. That works fine except for the transition moments where you put it on or take it off. I invariably wore wetsuits when scuba diving (up to 8mm, I live in Oregon) and getting the thing off required more than a little care. That’s obvious; just don’t get distracted
As for accuracy it’s a design decision. The Contour has always agreed well with the Dexcom’s I’ve used but it never agreed with the Abbott FreeStyle test strings; they read lower than the Bayer (at the time) strips. The manufacturers of test strips have to calibrate to meet legal requirements; they don’t want to be sued for low blood sugar, so there may be systematic differences between test strips from different manufacturers (aka legal teams.)
Traditionally CGM sensors had to be calibrated. The modern ones (G6+ for Dexcom and, I assume, Abbott 3) don’t require that but many people still calibrate. Being only 10mg/dL high is no big problem, being 10mmol/L high is a big deal. I assume you are using the US units
I’ve been using libre 3 for about a year now. Was pricking my my fingers a minimum of 4 times a day before that. Been an awesome change overall. I found the learning curve wasn’t too bad. The worst part is definitely opening the Libre. I have a shoulder that dislocates frequently, I am scared it might pop out trying to get in that thing! One tight jar of pickles!
Perhaps moving off-topic but there is another thread somewhere about the same problem with the Dexcom G7 inserter.
I paid more attention this morning when I was inserting my next G7 and, yes, it takes a lot, too much, effort to screw the cap off.
The Dexcom has the second problem that it has to be inserted on the back of the arm (in the US) and doing that requires a contortion involving twisting, pushing then, while still pushing, pushing a button at 90 degrees.
I think the Dexcom inserter itself requires an inserter; something to hold it and make all this pushing and shaking easier for those of us soon-to-be-DWMs.
It is an excellent opportunity for those with ambition and a 3D printer; in broad principle I can see how to make such an inserter-inserter but I lack the first two qualifications.
So, thank you all for your answers. Went in the ocean yesterday, and no problem with the adhesion.
On the other hand, I swear this entire batch of sensors is defective. First two wouldn’t open at all. This one is alerting constantly, mostly for highs. I started keeping track of the readings with my contour plus, and the libre is consistently 30 points or so higher than the contour on the high end, and 10-15 points lower on the low end. Obviously it wouldn’t be as much of a problem if I hadn’t had a cortisone shot last week. Usually I can compensate for the steroids by raising my basal immediately upon receiving the shot, but it didn’t work that well this time, and with the darned sensor going off constantly, my poor friend, with whom I’m sharing a beach cottage, has been awakened at least 3 times a night for the past 4 nights. Needless to say, she’s not a happy camper, and neither am I.
I’ve no clue what’s going on, but I’m calling my endo as soon as I get home. I am so lucky that I don’t produce ketones!
Glad you are having fun at the beach. I got to go to the coast last weekend where the high was 65 which was lovely. Its been 104 at home.
Are you using the Libre app on your phone? After you check the number with your contour there’s an option to snooze the alarms under Menu | Alarms | Silent Mode.
When you talk to your endo about the CGM it is important to specify both the CGM value and the BGM value. CGM performance is complex and “10-15 points different” doesn’t convey enough information to know if it is working correctly.
A CGM isn’t expected to match a BGM value. Handling the differences, which can be large, is part of the patient education that is the reason CGMs require a prescription when used for treatment decisions. For example, if your BGM says you are 180 the CGM can read up to 252 for a little bit and still be working fine. So definitely make an appointment with your endo or a CDE to get that education.
Even if the Contour is reading exactly on those errors are well within range even for test strips and there really don’t seem to be any precise “accuracy” requirements for CGMs at present.
A test strip (by the new German [IRC] regulations) can be up to 15% out 95% of the time and more than 15% the other 5%. For readings below 5.6 (100mg/dL) the limit is +/-1 (15mg/dL). That means two test strips can have twice that difference (under certain circumstances).
My Dexcom CGM agrees well with the Contour at around 6 (110mg/dL) but it typically but not always reads low below that and high above it. Given the inaccuracy of CGMs that’s a safety measure but it can be a royal pain.
Swimming for extended periods certainly causes instability in my BG; I used to swing all over the place until I started using a loop system on my pump. Depositing my posterior on a chair and using the computer all day was great for my BG control though not for my health.
In the end, since it annoyed my wife and that is a somewhat permanent relationship (I hope) I simply turned off the audio. I wake up pretty fast if my BG goes low and if it goes high I wake up eventually. Truth to tell even though I have much better BG control I still wake up three times a night these days.
I don’t need the audio alarms and rather than providing any help they are completely counter productive; I can see the screen on my phone and 2 taps tell me my current BG:
Of course I’m a T1 so I always produce ketones; hitting 14 (250mg/dL) annoys me but is no big deal. Hitting 4.5 (80mg/dL) is much more of an issue but only in the day.
Again, thanks so much for the advice. I really appreciate you all.
New problem…just changed my sensor and I absolutely cannot get it to sync with my phone. This happened with the sample I had been given, but after fooling around with it for 20 minutes and giving up, about an hour later I decided to try one more time and, bingo!
So now I’m on the actual prescription. As you know, I couldn’t open the first two, but the third one opened and synced right away. I just changed the sensor for the first time, opened and inserted with no problems, but, yet again, I can’t get the darn thing to sync. I’ve already spent a half hour moving the phone around and no luck.
It’d be nice if someone somewhere would show a picture of the exact spot on the back of my specific phone where the NFC should be, but all I can find is “somewhere near the top of the phone” or “in the middle probably on the top but maybe anywhere.” This has got to be a joke!
Grrr…about ready to chuck the damn thing and go back to finger sticks.
It’s not too hard. Had the same problem when I started using Libre 3. Just put the top of the phone up against the sensor. As a picture reference it would be like holding the phone upside down and resting on the CGM. Doing that I have never had connection issues. I have been using one for about a year. And that is how I always do it.
As an aside, you will have quite the learning curve ahead of you. It’s very different from pricking your finger and test strips. But once you get used to it you won’t want to go back. Just remember to alternate between both arms when you have to swap it out. Also don’t watch videos on YouTube to get it off. I have tried everything under the sun moon and stars. But this is is the easiest way that I have found. After two weeks the adhesive is not nearly as strong. Just grab the circular part and pull straight out. I literally do that every time. And I don’t have any problems. Welcome to CGM club!
If you have an iphone it’s always the top of the back of the phone. While I have always found iphones to be super reliable the internet is full of reports of NFC failing on iPhone SE’s
I just had a Libre 3 sensor that I could not open on Monday. I’ve never had an issue like that before.
I actually grazed the sides of my fingers trying to get it open. I was traveling at the time so no tools. Ended up using a slightly damp towel for traction and managed to get it open after a while.
Of course, once I placed the sensor itself into my arm, it refused to sync up despite repeated attempts. Abbott just sent me a new sensor, and a biomed box to return the broken one.
Yep. Put a new Libre on last week. Hit a vein in my arm and blood was going everywhere. Couldn’t get it to stop bleeding Even after 30 minutes of trying. Had to take it off and put another one on. I don’t tell you that to scare you, but be careful where you put it. But I am biomed mine back to them as well and they sent me a replacement. I have never had a problem with their customer service. Also because I have a shoulder that dislocates frequently, I am having a MRI done soon. Since I have to take the sensor off for that, they’re sending me a replacement in that case as well.
Spdif: Brilliant! Thanks so much. I have a Samsung Galaxy S21 ultra. I’m going to try a new sensor first thing tomorrow and that diagram will surely help. I’ll let you know.
Spdif: You are a lifesaver! Just put on a new sensor and it took all of 2 seconds to scan! Everything else I had read was telling me to scan near the top, but the link you posted cleared things up…the NFC on my phone is in the BOTTOM third. No wonder I was having so much trouble scanning.
On another note, got a third sensor that won’t open. Yikes…I hope it’s just this batch.
And on yet another note…although I was only in the ocean once for a half hour (lousy weather most of the week), 14 days of showering and that dip in the ocean, and no problems with adherence.
Hopefully going forward there won’t be as many problems. But thanks to you wonderfully knowledgeable people, I should be able to lower my A1c a bit without having constant super lows.
The higher readings on the cgm, due to being closer to actual timing of bg rise? Also, I think the lows came because I was correcting too soon. I had completely forgotten to notice the arrow position. Yet another learning curve!
