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Very low readings on Freestyle Libre

Discussion in 'Blood Glucose Monitoring' started by tim.ejb, Jan 19, 2019.

  1. tim.ejb

    tim.ejb · Newbie

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    Hi Everyone

    I have just started using the Freestyle Libre system today and already there seems to be a problem. I took my first reading just before I started eating lunch which for me is the first meal of the day and it was 4.2 mmol/L. However, over the next hour and a half, it gradually fell in a straight diagonal line on the graph to the lowest possible position. (Reading "LO" which is 1.1 mmol/L). I do not feel at all unwell and I am thinking very clearly. Does anyone know what the problem could be?

    Thank you very much.

    Kind regards

    Tim
     
    • Hug Hug x 2
  2. Boo1979

    Boo1979 Other · Well-Known Member

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    The Libre can be very off in its calculations compared to home finger prick blood tests done via a BG meter - when I used the system for a while, the libre readings were often double or half the BG result.
    Some people seem to encounter more problems than others ranging from inaccuracy to allergic reactions
    Abbot will usually replace a flakey sensor if you ring and discuss. They will ask for the resturn of the faulty sensor and for comparative BG readings
    If you self fund, Abbot are very poor at reimbursing you for sensors if you develop an allergic reaction and are unable to continue using the system - I had 6 when I developed an allergic reaction - Abbot would only reimburse me for 2 but in the end reimbursed for none as they said the 2 I returned using the prepaid Abbot return bags, had never been received
     
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  3. Scott-C

    Scott-C Type 1 · Well-Known Member

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    Hi, Tim, and I see you've just joined, so welcome to the forum!

    What you describe cam be quite common on the first day.

    When you attach the sensor, two things start happening.

    First, you've just poked a big needle into your skin causing a microscopic bit of damage to the area.

    Second, the sensor filament is in your body and is regarded as a foreign body.

    So, repair mechanisms to repair the puncture spring into action, and so does foreign body response mechanisms to try to fight off the "invader".

    Both of those mechanisms use cells which chew up glucose to fuel their work, so the glucose in the area will be depleted because they've ate it, so there is less for the sensor to measure, so it appears as a low.

    Also, the filament can take a bit of time to settle in, so can be skew whiff.

    What a lot of us do to get round these issues is attach the sensor and then leave it for about 12 to 24 hrs before activating it (the 14 days only starts counting down once you start it, so you don't lose any time).

    Doing it that way, the 24 hrs gives the repair and defence responses time to settle down so they're not influencing the reading as much.

    With yours, you might find that it settles down tomorrow.

    If not, Abbot are normally quite good at replacing them if you give their helpline a phone.

    They're definitely useful devices, no doubt about it, but some of the sensors can be plain off. If you use them for a while, you become more adept at identifying whether it's a "good" or "bad" sensor.

    Even "good" sensors can run a bit too high or low, but provided it's consistently so against bg checks, it's easy enough to just mentally add or subtract the difference to get a clearer idea of what the actual number is.

    There's also third party transmitters, blucon and miaomiao, which turns it into full on cgm, and the apps for those can be used to calibrate readings against bg checks - these can really tighten up readings.

    Good luck, although it has flaws, it can be a real game changer omce you've sussed it out!
     
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  4. Kittycat_7_

    Kittycat_7_ Type 2 · Well-Known Member

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    Hi,
    Welcome to the forum
    Tagging @daisy1 for her pack
    Hope you get this issue sorted.
    Take care
     
  5. tim.ejb

    tim.ejb · Newbie

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    Hi Scott

    Thank you very much indeed for your very informative reply. I was actually about to take the sensor off my arm before your reply but I will now wait until this time tomorrow. It is still saying "LO" but I hope that tomorrow it will be working properly.

    If it is still not working tomorrow then it seems like very bad luck that my very first sensor is a dud. If I had failed to install it on my arm correctly then would it have given a reading of 4.2 mmol/L to begin with?
     
  6. Scott-C

    Scott-C Type 1 · Well-Known Member

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    This actually reminds me of my very first sensor more than two years ago!

    I didn't know about the 24 hr pre-attachment gig at the time, so just attached and activated.

    I decided I was going to test more frequently than I normally do just to get a clearer idea of how it worked.

    The first few hours were absolutely fine, then it started to wander, so I thought, what's going on here, it was showing artificial lows, so like you I thought I'd been sold a pup. But it settled down ok the next day.

    The only thing I can think if to explain this is that maybe the response mechanisms take several hours to kick in, so it reads ok to begin with, then wanders till things are fixed and foreign body response realises it's not going to win.

    I recall I crashed skiing years back, hobbled off the slope but wasn't in much pain, but about 6 hrs later, it was absolute agony, turned out I'd torn a knee ligament. That suggests that the wide variety of bodily processes can take a while to start, ao maybe something similar is going on with libre, but I'm just speculating.

    If you're interested in the science behind it, there's a lengthy technical article about it at the link below.

    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2903977/

    The science is way beyond me, it's aimed at doctors, but it's an interesting review of the history of cgm, the problems, and the difference between bg, which your meter measures, and ifg, which libre measures.

    It's where I first read the snippet about how repair and fbr mechanisms suggest settling time is a good idea before activating (so I didn't just make that bit up - doctors say it's true!)

    You've not mentioned your diabetes type. If you're T1, I found Sugar Surfing by Stephen Ponder, a few quid on kindle, really useful when I first used libre. Lots of tips on getting the most out of cgm. The hospital I attend recommends it as further reading in their cgm guidance, so he's not a crank.
     
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  7. tim.ejb

    tim.ejb · Newbie

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    Hi Scott

    Thank you again very much indeed for another very informative reply.

    As far as I am aware, I don't actually have diabetes. I am currently on a ketogenic diet and I am hoping to be able to use this device to help me find out which foods and sweeteners etc will spike my blood glucose and I don't want to have to keep sticking needles into my fingers.
     
    #7 tim.ejb, Jan 19, 2019 at 7:36 PM
    Last edited: Jan 19, 2019
  8. tim.ejb

    tim.ejb · Newbie

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    Hi Kittycat

    Thank you very much. That is very kind of you. :)
     
  9. daisy1

    daisy1 Type 2 · Legend

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    @tim.ejb
    Hello Tim and welcome to the Forum :) Here is the Basic Information we give to new members and I hope you will find it interesting and helpful.

    BASIC INFORMATION FOR NEW MEMBERS

    Diabetes is the general term to describe people who have blood that is sweeter than normal. A number of different types of diabetes exist.

    A diagnosis of diabetes tends to be a big shock for most of us. It’s far from the end of the world though and on this forum you'll find well over 235,000 people who are demonstrating this.

    On the forum we have found that with the number of new people being diagnosed with diabetes each day, sometimes the NHS is not being able to give all the advice it would perhaps like to deliver - particularly with regards to people with type 2 diabetes.

    The role of carbohydrate

    Carbohydrates are a factor in diabetes because they ultimately break down into sugar (glucose) within our blood. We then need enough insulin to either convert the blood sugar into energy for our body, or to store the blood sugar as body fat.

    If the amount of carbohydrate we take in is more than our body’s own (or injected) insulin can cope with, then our blood sugar will rise.

    The bad news

    Research indicates that raised blood sugar levels over a period of years can lead to organ damage, commonly referred to as diabetic complications.

    The good news

    People on the forum here have shown that there is plenty of opportunity to keep blood sugar levels from going too high. It’s a daily task but it’s within our reach and it’s well worth the effort.

    Controlling your carbs

    The info below is primarily aimed at people with type 2 diabetes, however, it may also be of benefit for other types of diabetes as well.

    There are two approaches to controlling your carbs:
    • Reduce your carbohydrate intake
    • Choose ‘better’ carbohydrates
    Reduce your carbohydrates

    A large number of people on this forum have chosen to reduce the amount of carbohydrates they eat as they have found this to be an effective way of improving (lowering) their blood sugar levels.

    The carbohydrates which tend to have the most pronounced effect on blood sugar levels tend to be starchy carbohydrates such as rice, pasta, bread, potatoes and similar root vegetables, flour based products (pastry, cakes, biscuits, battered food etc) and certain fruits.

    Choosing better carbohydrates

    The low glycaemic index diet is often favoured by healthcare professionals but some people with diabetes find that low GI does not help their blood sugar enough and may wish to cut out these foods altogether.

    Read more on carbohydrates and diabetes.

    Over 145,000 people have taken part in the Low Carb Program - a 10 week structured education course that is helping people lose weight and reduce medication dependency by explaining the science behind carbs, insulin and GI.

    Eating what works for you

    Different people respond differently to different types of food. What works for one person may not work so well for another. The best way to see which foods are working for you is to test your blood sugar with a glucose meter.

    To be able to see what effect a particular type of food or meal has on your blood sugar is to do a test before the meal and then test after the meal. A test 2 hours after the meal gives a good idea of how your body has reacted to the meal.

    The blood sugar ranges recommended by NICE are as follows:

    Blood glucose ranges for type 2 diabetes
    • Before meals: 4 to 7 mmol/l
    • 2 hours after meals: under 8.5 mmol/l
    Blood glucose ranges for type 1 diabetes (adults)
    • Before meals: 4 to 7 mmol/l
    • 2 hours after meals: under 9 mmol/l
    Blood glucose ranges for type 1 diabetes (children)
    • Before meals: 4 to 8 mmol/l
    • 2 hours after meals: under 10 mmol/l
    However, those that are able to, may wish to keep blood sugar levels below the NICE after meal targets.

    Access to blood glucose test strips

    The NICE guidelines suggest that people newly diagnosed with type 2 diabetes should be offered:
    • structured education to every person and/or their carer at and around the time of diagnosis, with annual reinforcement and review
    • self-monitoring of plasma glucose to a person newly diagnosed with type 2 diabetes only as an integral part of his or her self-management education

    Therefore both structured education and self-monitoring of blood glucose should be offered to people with type 2 diabetes. Read more on getting access to blood glucose testing supplies.

    You may also be interested to read questions to ask at a diabetic clinic.

    Note: This post has been edited from Sue/Ken's post to include up to date information.
    Take part in Diabetes.co.uk digital education programs and improve your understanding. Most of these are free.

    • Low Carb Program - it's made front-page news of the New Scientist and The Times. Developed with 20,000 people with type 2 diabetes; 96% of people who take part recommend it... find out why

    • Hypo Program - improve your understanding of hypos. There's a version for people with diabetes, parents/guardians of children with type 1, children with type 1 diabetes, teachers and HCPs.
     
  10. garyog48

    garyog48 · Newbie

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    Thanks, that's quite helpful, I have found it to be very inaccurate a lot and have spoken to abbot about it.
    I have found it to always be between 2 and 5 points lower than finger prick and just use it as a guide to see which way blood glucose is going. Gary
     
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  11. NickySt

    NickySt · Newbie

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    Just signed up and reading this has been so helpful as I couldn't understand the discrepancy between doing a finger prick test and reading off Freestyle Libre and had been finding it was consistently lower. (i.e. shows me to be low for hours on end when in fact I'm ok on finger prick) The tip on letting the sensor bed in for 24 hours is also helpful.
     
  12. CitizenX

    CitizenX · Newbie

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    I just purchased this product on 21 Nov 2021 and when verifying it against my Accu-Chek finger prick tester, I also find the readings of the LifeStyle Libre tester are about 2 mmol/L lower than they should be. This is pathetic. Had I know this product gives false readings there is no way I would have purchased this product. In my opinion it should be recalled and fixed since this company is screwing with our health.
     
  13. Smiler99

    Smiler99 Type 1 · Well-Known Member

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    I had similar problem I rand them up 1 have only had 2 successful libre and 2 faulty ones, (always conform with finger prick) I phoned them and getting another one sent out.
     
  14. jape

    jape Type 2 · Well-Known Member

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    @tim.ejb

    Hi Tim, I am on my 62nd sensor now, and only have had one with a similar experience than yours. When I called Abbott here in Canada, they replaced without any real hassle. They asked me to return the faulty sensor, but then they did not include a return envelope.
     
  15. KennyA

    KennyA Type 2 (in remission!) · Moderator
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    Just had my second Libre fail. Two used, both as part of the "free trial", and both failed. This one at least lasted a few days before packing it in, and initially conformed well with the fingerprick reading. It was showing dips into hypo territory overnight, which was the reason I wanted to try it. It failed completely last night. However, for its last two days it insisted my BG was around 3.4. Sometimes as high as 3.7, but always in "do something about it" territory. I felt fine and fingerprick was showing 5.1, so I wasn't too bothered but according to the Libre I went over 24 hours "hypo". I'll ask for another tomorrow, but this really isn't convincing me that I'd want to spend money on it.

    Edit to update - Abbott have (reluctantly) agreed to send me another sensor. They initially refused as I was honest and said I'd fitted the second one to my chest, following advice from long-time sensor users, because often the ones on the arm failed if you slept on them. They did eventually agree to do so but I think only because the reasons for the initial failure were acceptable. I have also told them that at the minute I can't see why anyone should pay to have such an unreliable piece of kit - it's OK for me as a T2 and able to go back to fingerpricking but for anyone depending on it it would be at risk. It did cross my mind that maybe the batch of sensors being used for the free trial might be experimental in some way - and the free trial is a means of engaging a lot of beta-testers. The reputational damage done would however be a huge risk....
     
    #15 KennyA, Nov 28, 2021 at 7:26 PM
    Last edited: Nov 29, 2021
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