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Freestyle Libre Sensor: highly inaccurate??

So 3hrs after polishing off the wife's chicken noodle dish I was feeling pretty smug with my glucose levels - only to discover a massive overnight rise upon waking this morning! Sigh.

But anyway - as this thread is about inaccuracy of the Libre I thought I'd do a few measurements with my trusty Glucomen at the same time. (Libre sensor was applied Thursday evening about 4hrs before activation and seeing the 3.3 reading).


When I tried something like this before, the Libre was reading lower at the bottom end of the scale and higher at the top end. Looks like this one might be consistently lower.
 
I’ve been using the Libre for about a year; so over 20 sensors including 3 faulty ones that Abbott replaced. A few points from my experience:

1. At present, Asda pharmacy are selling sensors for £44 IF YOU can show you have diabetes. Plus they can get them within 2 days (Abbott are taking 3 weeks to deliver.)

2. The first 24 hours of a new sensor is very inaccurate so I don’t activate mine for 24 - 48 hours, else it’s a waste of money.

3. Sensors do not measure blood glucose, but the software tries to predict a similar reading. There is often a 10- 15 min delay behind a finger prick blood glucose (BG) reading. This only matters if BG is falling/rising quickly. Sensors are also less accurate when having/close to a hypo, but at least I get more warning of an impending hypo.

4. Typically, the sensor reading is 0.5 to 1 mmol below my BG reading, so I see this as being on the safe side. I only had one sensor that reported higher readings than my BG meter and that was a faulty sensor.

5. I was in hospital a few weeks ago and had a particularly accurate sensor. It was usually the same or within 0.1 mmol of the hospital’s BG meter (that they calibrated every time) - very impressive!

Generally, I find the Libre to be accurate and “life changing” in managing my diabetes and also reducing stress/anxiety.

Ps. I self fund and have no connection to Abbott.
 
Hi. I became type 1 when 16, 57 years ago, and in my very long diabetic experience I tried so many different ways to survive with my problem that when Abbott’s Libre appeared, I was sure of a miracle.

Now, after 15 months of its use, I'm still of this opinion, and I'll explain why.

!- The Libre itself has many advantages, all well pointed many times in these posts.
But... (there is always a "but", alas!), in the first summer of use I had a total defeat of its performances, 6 sensors were changed by Abbott, due to very erroneous and erratic values. The probably good explanation was that the shipment was done for all of them by truck on very sunny days, with a courier with black painted trucks and no air-conditioning, which probably stopped along the way for some time in full sun... Anyway, all over the 15 months of use I needed to change 5 more, randomly distributed in time, in total 11 over 31, so this looks a great problem.

2- And here the second miracle: on August last year I bought a Bluetooth transmitter from a German startup, and the trio Libre-BlueTooth Transmitter-XDrip+ App solved definitely this problem.
Now I have ALL the libre sensors that work flawlessly, even when inaccurate, because XDrip+ has a very accurate calibration algorithm that corrects the Libre values with the blood ones (2-3 a day) taken with a glucometer.
If my corrected readings go over or below the given parameters an alert starts on my smartphone, by day and... MIRACLE! by night.

Having been 11 times in heavy hypoglycemic night crisis, with consequent hospitalization and all the connected health problems, I was used to go to sleep at 04 AM, given that night hypoglycemias occur before...

Now I can go to sleep at 00 AM, sure that it is checking that everything goes OK, all the night long.

So, given that now there are on sale at least three different transmitters like mine, and many more in the next months, I strongly suggest to follow my example. My little cent. Bye. Pippo
 
Do you have a link to purchase the German transmitter? I was only aware of an American one, but would rather buy European.
 
11 sensors faulty out of 31. There is clearly an issue. To be honest, if it's that unreliable, I don't even know why the NHS would ever consider funding this.

Sounds like adding calibration from blood samples from time to time would bring accuracy to the device, so I don't understand why Abbott doesn't include such functionality in their mobile app.
 
Mel dCP said:
Do you have a link to purchase the German transmitter? I was only aware of an American one, but would rather buy European.
Click to expand...

Hi, Mel, hat-tip to a poster jroth on an American diabetes website who recently posted the thread linked below, with links to other transmitters, two in Germany and one in Poland:

https://forum.fudiabetes.org/t/freestyle-libre-transmitter-for-selfmade-cgm/3594

The Polish one is a new one on me, but I'd been having an occasional look at Sandra Kebler's bluereader project as it developed.

Haven't followed them much as I'm happy enough with blucon, but they seem to be at various stages of protoyping and pre-ordering, so you perhaps wouldn't get one through the post in a few weeks.

Both bluereader and sweetreader look a bit clunkier to wear than blucon, which is a relatively compact device.
 

I agree, Abbott should include this in its App, but being a big company its times are longer than the small companies’ ones.
I'm sure that they are studying a Bluetooth device that will surely be smarter than the one I use now, but probably it's still on the drawing boards, while BlueReader, Blucon and (I think) DexCom are working now (and very well, as in my experience).

TedTomato said:
11 sensors faulty out of 31. There is clearly an issue. To be honest, if it's that unreliable…..
Click to expand...

I disagree about Freestyle unreliability, because last summer debacle with 6 sensors OFF was due to external events, so the real number is 5 over 31, not so bad.
Moreover, and this is very important IMO, as you know Abbott is ready to substitute all the unreliable stuff, so no money lost by the users.
But please give a second look to the advantages of Libre plus BlueTooth transmitter (any!).
Have you ever gone in deep nightly hypoglycemia?
I hope not for your safe, but if yes, would have not been wonderful if someone or something could wake you before reaching coma?
It happened me many times, as I told, and I bless my fortune to be still alive with the possibility to use now such devices, that allow me to sleep safely.
I think in the world actually only a few hundred people use Bluetooth transmitters to connect their FGM to SmartPhone or Smartwatch, but I’m sure that in the future the number will increase exponentially.
Believe me.
All this, obviously, waiting for new outstanding technologies that are just round the corner, and will surprise us in a few years. Bye. Pippo
 
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Mel dCP said:
Do you have a link to purchase the German transmitter? I was only aware of an American one, but would rather buy European.
Click to expand...
Hi Mel, I would be pleased to give you the address, but I think it's not ethically right to do it, so I'll just give you the transmitter's name, that is BlueReader by Sandra Keßler.
You'll find easily all what you need in the web.
Good luck.
Pippo
 
Just wondering how you know your meter is accurate? Did you conduct an accuracy test on it. Is it a model that has passed the new accuracy standards from 2016.
There will be differences between a Libre and Meter as they measure different fluids, they could both be right
 
Boots are charging you too much, complain to their Head Office - Check other pharmacies like a local one or Lloyds, Asda
 

In term of comparing readings from blood glucose testers and the Libre readings, I have 3 blood glucose testers, so comparisons haven't been done with just one device.

The usual justification is: "the Libre is measuring different fluids, not blood glucose etc, so therefore readings can't be compared".

This argument makes no sense to me. It's sold as a device to report blood glucose levels, shows readings in mmol/L etc.

It's as if I was putting a new scale on the market, and saying "it's measuring weight a different way, extrapolating value to kilograms, and sometimes it's right, sometimes it's wrong". People wouldn't say: don't worry about its accuracy, it's measuring weight in a different way...

The Libre is designed to extrapolate information gathered, and display it to patients in units they understand, and they can compare with other devices showing the same units, or results from their doctors.

If the device is measuring something else, and can't extrapolate accurately to something known, then it shouldn't be marketed as such.

It should just be: latest reading is 452 "bits" in interstitial fluid, and we won't tell you what's a bits. You will be able to see it going up and down, but sometimes the trend will be off too. Would people buy it?

I think those sort of devices are going to change dramatically the way blood glucose levels are understood, but it seems early stages still.
 
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@TedTomato These devices are a long way from being perfect, but they are very useful.
I've an idea that with regard to the Libre, Abbot refer to "Glucose Monitoring" not "Blood Glucose Monitoring". I may be wrong.

Ignoring the Libre, have you tried comparing your 3 blood glucose testers over a few hours?

In essence Dexcoms and Libres display blood glucose readings from about 15 to 20 minutes ago.
Try doing a blood test, waiting 15 to 20 minutes, then comparing to the CGM reading.
 
I had 3 out of 4 like that. I have now given up on them as it seems frustrating and completely pointless to use this device.
 
I’ve come to the conclusion that some people get lots of ‘faulty’ sensors.

Other people, like me, seem to get great results and consistent accuracy. I’ve had 20+ sensors, only returned one, and that fell off.

I guess my body and the Libre work well together.
And it seems likely that there are other people at the other end of the spectrum, whose bodies, do not work well with the Libre.

But i do find it surprising that those people seem to keep trying over and over again, and then blame the Libre, when it could very well be their own body’s reaction causing the inaccuracies. And if it is their own body, that won’t change, so keeping on trying, and keeping saying it is Freestyle’s fault, seems rather pointless.
 
Brunneria said:
I’ve come to the conclusion that some people get lots of ‘faulty’ sensors.
Click to expand...

Very convenient to just blame the individual, not even wondering if this technology has been released to the market just a tad early. Just because it works for you, and not others........To actually not refund the considerable cost of this item to the individual if found not to be suitable is really none too ethical either......but then again, I have the feeling that this company sees its present customer base as one big R&D project. I think the company have over inflated the usefulness of this device, knowing just how many diabetics long for the freedom of a device which does all the work for them, instead of having to constantly fingerprick all the time. I had 3 out of 4 failures with sensors provided. Not good enough when I'm paying for it. I wouldn't accept that kind of failure from any other device I buy, I'm afraid. Oh, and before it is even mentioned, they were all applied exactly as per the company's instructions. You wouldn't keep a car you could only use 25% of the time, would you? I think the company saw a massive opportunity to extract money from the NHS. Luckily most Health Trusts have seen fit not to provide this device and have stuck with what they have. I prefer to have something a little more accurate if I'm basing my insulin dose on it. The results I received from the device were wildly innaccurate, despite following all instructions to a T. You seem to imply that sensors aren't 'Faulty', but the issue is user error? Forgive me if I'm wrong, but surely the large number of people complaining of issues with this device aren't all wrong?
 

My personal experience is this. I have 2 freestyle monitors. I had misplaced one so my gp gave me another. I then found my first one. I got a bit suspicious of the readings. So decided to use both concurrently to see what they say. Both gave opposing readings. Even though I tested within Seconds of each other. So I now use the monitor as a guide and not the gospel truth.
 

You are the one who introduced the word 'blame'.
The world is full of things that work for some people and don’t work for others. No need to make it about blame.

Do we blame the individual when they have a food intolance? Of course not. They have to avoid particular food but we don't blame them.

Nor do we blame people who have drug contraindications - they get offered (or choose) an alternative, if one is available.

People (like me) who have sensitivites to adhesives on some medical tapes, only find out once they have a rash, or worse. And the next time we use a different brand, until we find one that works. I am actually amazed every time I put on a Libre sensor that I don't errupt in weeping red sores. I spent my first £150 on the Libre expecting the whole thing to be a total failure for exactly this reason. I weighed the risks and decided to try it. I would not have blamed Freestyle if I got a rash, just as I do not blame other medical glue manufactures if their stuff works better on other people than on me.

At the moment, the Libre is one of a small group of gadgets that measure blood glucose in a certain way.
As time goes on, other brands will join the party and the customer will have more choice, which will probably include a range of adhesives, and a range methods of reading blood glucose - and for each of those, there will be people for whom they work well, and people for whom they work badly.

And as for cost - my wardrobe and my house all contain a few items that I bought thinking they would be fantastic, but which have fallen short of my expectations. Three things are certain though
- I return them if faulty
- I don't buy any more of something that doesn't work for me
- and I don't think that because it doesn't work for me, the manufacturers are automatically dishonest, incompetant and con merchants (we get accusations like this about the Libre quite often. One poster actually started a thread about it a year ago. Apparently she had gone on every review site and forum she could find, accusing Freestyle of dishonesty, corruption and so on. Only on the internet, eh?).
 
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