Hi my name is Katie… I have been on the Freestyle Libre for 3 weeks now. My reader is ALMOST ALWAYS 16-20 points LOWER than a blood stick. Found out that if you are any way DEHYDRATED… your readings WILL BE OFF !!! That’s because the sensor tests Interstitial Fluid… NOT Blood glucose. I bought a MIAO-MIAO and have never been able to get it to sync up with my IOS iPhone 6plus , iPad or Apple Watch. So far a waste of 214.oo dollars. Came with NO instructions. And YouTube instructions haven’t worked either. From what I’ve read, NO FREESTYLE readings will be exactly the same as a Blood stick… Once you realize this you won’t be frustrated. Wondering if anybody else’s Libre is off as much as mine?
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Mind was off by 50 points the other day. I called to talk to the company… save your time if you are thinking of doing that. They ask a bunch of questions and find a way to say that it isn’t their fault. My last off reading… they said I need to use their strips to test… Not my meter. I’m using mine for trending only right now.
It can be way off, when it’s just 10-20 points lower I can consistently adjust that amount. But some of them are 20 one time and 50 another or 50 lower all the time and who wants to give insulin off of adding on 50 points? And one sometimes was even higher sometimes instead of lower although that’s rarer. I can’t deal with large numbers off or inconsistent amounts off…
Some suggestions when you call them to save frustration, I bought a pack of their strips to just use for when I call them for a replacement. Plus outright request that you want a replacement and if they don’t your pharmacist you buy them from should. My pharmacy has never blinked about ordering me free replacements. Their strips are awful too as they require a lot of blood so I would never use them everyday anyway, they are just for testing when I am calling them. It also really varies what kind of response you get depending who you talk too, the last time I called I got told they aren’t reliable for the first 3 days ??? What?? I still insisted I wanted a replacement and they sent it. If they ever stop replacing them and the pharmacy stops, I will be the first one to stop and switch to a different CGM!!!
They also have more competition coming out soon so they need to be nice or they will lose a bunch of people!!!
I still like using it, saves a lot of fingersticking. I scan all day and it has been helpful to find out I dropped or am I higher than expected and I didn’t have a clue. The one I am using now is about 20 points off and I just add 20 to my number when making adjustments. I also overlap when I start a new one so I can compare for about 6-8 hours of readings. That helps me know how the new one is working. The new ones are always way off for the first couple of hours.
I just posted on a different forum: 90 day clinic visit after using the Libre almost exactly for those 90 days: The A1C was worse than the Libre showed as a 90 day average, but, not by much. The difference in averages, if you want to look at it like that, was minimal.
You may want to consider where you are placing the sensor. If I place it lower on my arm it’s readings are guaranteed to be off but if i place it high up and slightly towards the inside of my arm like the one I have in right now it is spot on at least for me.
By sync with the phone, etc do you mean you are trying to use it without an app? Because the apps available like Spike are really good at instructing you on how to connect the various Libre add-ons. I don’t have the Miao Miao but the Nightrider and it took a few tries but it connected once I figured out what I was supposed to type in.
I would go onto Youtube and look up Nerdabetic. He has great videos on the Libre and related apps and add-ons and he always answers comments promptly. If that still doesn’t work then contact the company and ask for a replacement or refund since it could be defective.
That’s a common, known issue with Libre. I used it for about 2 years, from when it first came out over here until September 2017. My conclusion is that problem is the lack of calibration possibilities. There are different possibilities to make it work as CGM which also give you a possibility to calibrate, but it will never be as good as Dexcom, for example.
Marie20…Wish I had seen your post earlier… Just got off of phone with Libre and won’t replace… 2nd sensor was knocked off after 2 days. Their paperwork says to REMOVE the sensors BEFORE having a CT, Xray, etc… She told me that if It fell off that it could be replaced but apparently she wasn’t listening to me that it got knocked off after 2 days… WHAT??? She said that " IF " I had saved the box and contents of the sensor… THEN they could have replaced it. Every sensor I’ve used so far has had mostly a 20pt. lower reading than a stick… I’m cool with that… Now I’m suffering from EXTREME lows hitting around 2 - 3 a.m. So low that the reader just says LO with no number… I do know that the reader can read as low as 47… Been there done that one morning too. Just blessed that I do wake up, right ? LOL I do know that I was severely dehydrated that morning and have been suffering with an UTI ever since. Going on 1 week + 6 days. Severe cramping in my calves to my arms and hands. Would love to get off this Diabetes rollercoaster now… Please? LOL
Hi Firenza… I’ve had 4 different sensors in 4 different areas… back and inside of left arm. Left side low over (ovary area) and now on right low over exact area… ALL still have the 20 pt. lower than a stick… so I just add 20 to Libre reader… If in question… I test on BG meter Accu-Check Aviva Connect. (out of 3 meters from Accu-Check… Aviva Connect, Aviva, and the One Touch Mini… this one reads the lowest… and wouldn’t you know it… they are ALL 20 pts off from each other… Go figure huh? LOL. And as for the Spike App… I can get the APP on my phone… I can’t get the Spike App to find the MiaoMiao… Has never had ANY readings show up on my devices… Have watched YouTube videos… Did the TESTFLIGHT app that the MiaoMiao said to do first to get the Spike app… My granddaughter said that I should have gotten a message that would have told me that it was syncing up… NOPE! Wondering if I got a bad MiaoMiao… how would I know? Thanks for responding! In your response what did you have to type in that you weren’t doing, if you don’t mind me asking.
I kept on typing in the beginning numbers instead of the ending numbers that were printed on the side of the Nightrider. Can you try taking it to a techie friend or something? If you still can’t get it working then you may have a dud.
I use the blucon nightrider waterproof version, but only because I didn’t know about the miao miao until after I had the blucon. As far as the miao miao, it sounds like you may have a bad one, and i’m sure they will replace it. Most people prefer the miao miao’s bluetooth connectivity over the blucon. I also recommend the xdrip ios, as you can calibrate with bloodsticks. My endocrinologist also warned me against comparing the libre to bloodsticks during rapid blood glucose changes such as eating, insulin injections, and exercise, as the glucometer itself usually claims it may be off during those times. The verio iq manual said ±70mg/dl.
Seems counterintuitive, however, it made sense. If you are fasting and you believe your blood sugar should be stable, and it is still off, calibrating should correct it. If you calibrate during an insulin injection, or exercise or eating it is supposed to throw the algorithms off.
Hi Katie,
I have been using the Libre for several months and I find it to be as accurate as a finger stick. Blood glucose readings do respond to food and exercise more quickly than interstitial fluid readings, and that may be why your Libre readings seem lower than your finger stick readings. Your Libre readings may not have “caught up” yet, if you are comparing readings shortly after eating. Also, even finger stick readings are not always “accurate.” I switched to Libre from Dexcom. When I used the Dexcom, each new sensor had to be calibrated with two finger stick readings, one right after the other. I used to use the very same drop of blood for the two readings and would get surprisingly different readings — from the very same drop of blood! So, if you otherwise like the Libre, stick with it, and simply keep in mind that it will take a little longer to give you your “actual” reading than a finger stick would, and that your finger stick reading may not be “actual” either.
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Hi Marie. Just read your note on the Freestyle Libre. I’ve been using it for several months and I love it. I’ve not found that big a difference, ever, in my numbers. And, yes, I’m on insulin and need the number to be as accurate as possible. The only problem I’ve had is with the sensors staying on because I exercise and sweat a lot. But, I solved that problem with something called Simpatch. I’ve not had mine come off while using these. I have Humana and got a scrip for 150 strips and my cost was $2.60. I had put on a new sensor the day I got them and these strips use no more blood than the ones I’d been using before and it’s so much easier to, just, carry the reader and strips rather than the reader and another glucose monitor. As I mentioned, before, I had problems with them staying on the 10 days and Abbott was very nice, when I called, and have replaced every sensor that fell off. I’ve found doing business with them is very easy. I love my Libre because I can check my sugar when I do my 4 mile walk 3 days a week and at night I don’t have to get up and stick my finger. I had a low blood sugar episode that sent me to the emergency room last year and the Libre has helped me, tremendously, in this respect. I’ve never had my blood sugars be off by 20-50 points, the first 3 days, since I’ve been using mine. I can’t afford to go to the Dexcom. It’s more expensive than the Libre.
Here’s hoping you get your problem taken care of because these CGMs are the best things in the world for diabetics. It’s changed my life for the better. And, one good thing is that my husband can take my reading, during the night, and doesn’t have to wake me. 
Good luck!
roger5 May I ask a stupid question? how do you calibrate the Libre? I was not aware that you could change anything on the reader. I do not have the strips to the Libre yet. I’ve only looked at WalMart… will have to stop at Walgreens Rx where I bought my Libre. I too use the SimPatch to hold my sensors on ( just be aware that when removing they can cause bruising when being pulled off sensitive skin areas. Been there done that! LOL )
You cannot calibrate the libre reader - the apps that they use get the calibrations - glimp, xdrip - etc
You can get a countour next meter off ebay for 6 bucks - strips much easier to use then freestyle
You need the libre reader to start the sensor, once it is started, you can use the xdrip app on android phones, or use spike or xdripios for iphones. I was severely disappointed that the libre sensor did not have alarms, as I was on the Dexcom for a while before my insurance told me it wasn’t covered anymore with the current plan. But with a different plan it would be covered, just speak to your corporation… which did not work. Anyways… I was used to the alarms, and stumbled on ambrosia systems BLucon NightRider which offers a waterproof version for a one time purchase of 165 plus shipping… I prefer it because I thought batteries would be better than rechargeable, as most phones only last a year or 2 at most, but most people prefer the miao miao which is rechargeable, but needs tape… I use arm sleeves and am now somewhat used to them, although in the summer, I use shin guard sleeves because all the arm sleeves are too hot. Anyway, the xdrip app is excellent and is usually a few points off the libre reader or verio IQ, and if it is off, there is usually a valid reason, such as a recent meal, or recent insulin shot…I still use insulin pens. But usually the humapen savvio that I had to buy from Canada… I was using the Owen mumford auto pen but it won’t stop at the end if the cartridge like the savvio does, and it stopped working recently
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after my note I went to Walgreens and they had FREESTYLE PRECISION NEO test strips that are for use in the Freestyle Libre READER. I now have 5 different kinds of test strip meters. My fave before I found the strips for the Libre Reader is the DARIO… fast, small, compact and uses my phone instead of carrying a separate meter. So when my Libre tells me to do a finger stick… I used my Dario, But now will start using the Freestyle strips with the reader. Miao Miao contacted me and has said that I can return my device, but won’t send a new one till they have mine. Hoping they are on the up and up. Going to uninstall my SPIKE app on all devices and see if I can get it to sync up… wish me luck.
Using the United States version of the Freestyle Libre system, changing to my third sensor last night. Scanned after applying new sensor and reader said it would be ready in 12 hours. This morning, ready to do my first scan on the new sensor, reader said, sensor not working, remove and replace with new sensor. BIG disappointment. Called Abbott and they sent me a notice to my pharmacy to replace it. Excellent service from Abbott today.
That has not always been the case with Abbott. Customer service seems highly dependent upon the person you happen to connect with via phone. I could expand upon this but will refrain for this post.
As far as accuracy using the system over the past 20 days, I have found that it is seldom near my meter readings even taking into consideration the lag time between blood and interstitial fluid. At times it is 17-25 points lower than the blood reading via meter. The highest variation was around 30 points. The closest readings were about 3 points different.
While I find that very disappointing, I just mentally add about 20 points to whatever the reader indicates as long as I am in the ballpark with how I feel and my activity like pre or post meal.
I never adjust or make treatment decisions or alterations based upon the “number” shown on the reader.
I really like the system for the direction indications. How I peaked? Am I still climbing? Knowing the direction my blood sugar is going is a huge help to me.
Considering the difference in cost between the Libre system and other systems like Dexcom, I really don’t expect the Libre system to do everything a Dexcom does.
Since the Libre system is pre-calibrated at the factory, it would be nice to have the ability to change the calibration with each new sensor for those that desire to do so.
OK, I have rambled enough for my very first post so I will stop here.
Thanks to anyone that reads my post.
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Did you test your meter with control solution - you say it is seldom near your meter readings like the meter was gospel and correct
No meter is gospel. Commercial labs are not gospel. But I have taken my meter with me to a commercial lab and done a test simultaneously with the lab and the results were within 2 points of each other. I do trust my meter more than any “new to me” device until I have used it a sufficient amount of time.
When I have changed from one brand meter to another, I have tested with BOTH meters, from the same blood sample, to look for any differences and for consistency.
I have gone to different commercial labs and received very different results for a hemoglobin A1C drawn within an hour of each other. Nothing is fool proof, perfect, and always reliable.
From what I have read on this site, I am not alone in the opinion that the Libre system will indicate values below the meter readings. Even taking into account, the time lapse between blood and interstitial fluid, the meter appears to be more accurate and the meter values agree with how I feel physically.
I am not sure why your post has a snarky tone to someone that just joined the community today. I thought this was a place to voice our experiences and help each other. I am sorry if my posting(s) gave you the impression that I feel my meter is infallible. It has been my only source (until recently) of “at home” information for many years and has provided considerable accuracy when compared to commercial labs.
And, YES, I use control solution.
I wasn’t knocking the Libre system, . . . I happen to love it. I just stated what I have experienced so far with it, that my sensor values are considerably lower than my blood values from my meter. The Libre system is giving me a lot of information that I did not have from meter use alone. You can’t use a meter while you are sleeping and the Libre system shows me a great graph of what happened while I was in dreamland. It indicates if my levels are still rising without having to lance my fingers every few minutes to see if I have peaked or not.
Any tool we can use to help keep better control of blood sugar levels is a good tool in my opinion – even one that has some drawbacks and limitations.
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Welllll @Tony24 is a little bit snarky (sorry Tony! 
) about when people describe CGM vs. finger sticks since I think he is a little bit tired of hearing people treat their meter readings as he said “as gospel” but he does have some really good experience with the Libre system and if you look at some of his other posts on it it’s not all good. Btw, that 20 point difference between your meter and the Libre simply could be the difference between meters and keep in mind that the Libre is actually an older technology so I personally don’t expect it to be infallible.
My experience with the Libre has been great except for a wonky sensor here and there and if you want more spot on readings then you may want to use an app like Glimp so that you can calibrate it. Welcome to Tudiabetes BTW.