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Made the plunge and bought the Freestyle Libre

Discussion in 'Blood Glucose Monitoring' started by JoeT1, Nov 5, 2017.

  1. JoeT1

    JoeT1 Type 1 · Well-Known Member

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    Hey all,

    As some of you know, I was only diagnosed a month ago. I purchased the Freestyle Libre out of my own pocket last week and applied the sensor last night. Of course, not waiting around, I immediately scanned the sensor to activate, and have been testing a lot overnight and today.

    I love the fact I can test as much as I want, that I can see the graph and so on.
    Now, 2 things.
    - I know they say it can take 12-24 hours to get a correct reading and comparable to the finger prick test. It seems to be big differences between the two, sometimes up to 3-4mmol....anyone seen this early on?
    - If I take a reading right now, it could be say, 14.2mmol, if i take the same reading 2-5minutes later, it can move up or down up to 2mmol

    I guess it's just giving it that initial 12-24 hours in order to start itself correctly?

    Hope everyone having a good Sunday
     
  2. Scott-C

    Scott-C Type 1 · Well-Known Member

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    Two things are going on in the first day or so. You've just stabbed yourself with a big needle so there'll be some localised inflammation at the insertion point. And you've left the sensor filament under your skin, which is regarded as a foreign body. So, you'll have repair cells trying to heal the inflammation, and defence cells trying to fend off the foreign body. Both of those mechanisms eat glucose to do their job, so until they settle down you'll get odd readings. It's why it's best to apply but delay activating for a day or so. It should settle down after a while, but if it remains well out, phone the Abbott helpline - they're normally pretty good at replacing duff sensors.

    Libre on its own is pretty good, but you can bling it up a bit to make it way more useful. Ambrosia Systems make a bluetooth transmitter called Blucon Nightrider for about 100 quid one off cost. Pop it on top of the sensor with a plaster, it takes a reading every 5 mins, bluetooths it to an an app on your phone, xDrip+ so you get way more useful graphs, see pic below, showing each 5 min reading as a blue dot instead if the 15 min average which the libre reader graph shows, so you can be much more precise about things. Also does predictive simulations to warn of possible lows well in advance, rings the phone if you go below a set level, so ideal for avoiding pesky night hypos. Plus you can send the results to a smartwatch too - ideal for the occasional glance to pick up on developing highs/lows and pin them with a small carb or insuin "nudge" before they get anywhere near becoming a problem. You can also calibrate it against blood to tighten up a sensor's sometimes dubious factory calibration.

    The makers, though, are a very small startup and seem to have been overwhelmed by demand so you might have to wait a while for an order to be delivered.

    Been using this setup for about a month now, delighted with it.

    Screenshot_2017-09-27-18-03-45.png
     
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  3. helensaramay

    helensaramay Type 1 · Well-Known Member

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    Regarding the difference between finger pricking and Libre, there are a few things to consider
    - time for your body to get used to a foreign body
    - the Libre readings are 15 minutes or so behind finger pricks
    - the Libre takes a reading every 15 minutes. When you scan, you are downloading the last reading (actually you are down loading the last 8 hours of readings) so it may be nearly 15 minutes old
    - any meter has a tolerance of about 10% (I think it is 11% but that makes calculations difficult). If they are wrong in opposite directions, the difference could be big in higher numbers. For example, if your actual value if 15, your finger prick could say 13.5 and the Libre say 16.5.

    You also ask about fast rises or falls. This depends what you are doing.
    If you have just eaten a mouthful of glucose (e.g. in response to a hypo), you BG can rise very fast.
    If you are exercising with some insulin on board, it could fall quickly.
    I have experienced a drop of nearly 5mmol/l in less than 30 minutes when running without managing my insulin correctly.

    Finally, the true value of the Libre is not in the replacement of finger pricks. It is the history and trends. Using a Libre for individual readings is equivalent to using a smart phone for making calls only.

    I was asked to write a blog for Diabetes UK about the Libre https://blogs.diabetes.org.uk/?p=9247. Might be useful to help understand what it does and how to get the most out of it ... unless you “pimp” it as @Scott-C describes.
     
  4. JoeT1

    JoeT1 Type 1 · Well-Known Member

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    Yeah, taken all this info on board.

    It's been just the 24hours now, and there is up there on 3mmol difference. This slightly aggravates me as I know that I can't take the data that has been captured and do anything with it.

    I'm more so worried that it's not going to fix itself, I mean, 10% difference is probably ok, only just, but when you have the likes of 1-3mmol difference, it's a bit frustrating. Especially when i'm high and i'm not sure as to why, as even though I have not been in target range much, I have not been this high consistently over the last week.
     
  5. JoeT1

    JoeT1 Type 1 · Well-Known Member

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    As you can see, reading are very erratic not far apart.

    Plus, the arrow system seems to be quite off?..

    [​IMG]

    [​IMG]

    [​IMG]
     
  6. barrym

    barrym LADA · Well-Known Member

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    I think you're looking for a level of granularity that isn't there. I posted a similar observation when I started, and I have subsequently seen that it is more dramatic changes that it indicates. There's a bit in the user guide that explains it I believe.
     
  7. JoeT1

    JoeT1 Type 1 · Well-Known Member

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    So I have carried out some tests this morning and afternoon. About 40 hours after activating.

    10.55am FP =11.7
    10.55am Libre = 13.8 (2.1 and 16% difference)
    11.05am Libre = 13.1 (1.4 and 11% difference)

    12PM FP = 10.0
    12pm Libre = 12.4 (2.4 and 20% difference)
    12.10pm Libre = 12.7 (2.7 and 22% difference)

    1pm FP = 10.6
    1pm Libre = 12.0 (1.4 and 12% difference)
    1.10pm Libre = 11.9 (1.3 and 11% difference)

    Not sure what to make of it. For example if I knew when testing at same time, difference is take 10% away from Libre reader, I could calculate. But when it's up on 20%, it's hard to gather info.

    How long would you wait before calling Abbot?
     
  8. barrym

    barrym LADA · Well-Known Member

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    You are doing the percentage difference between the two, and not between each and a lab test. I suspect one will be above and one below a lab test so both are within spec.

    As a matter of interest, after seeing so many people suggest putting a new sensor on for a day or two before activation I shall be trying that this week, to see if they come closer. My sensor expires Friday 7am, and I'll put the new sensor on the other arm on Wednesday morning.
     
  9. JoeT1

    JoeT1 Type 1 · Well-Known Member

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    I did not think of it this way. So even my finger prick test is going to have a different outcome to a lab test done on blood? Makes sense I guess. It does seem the lower the reading, the more in range it is. 10% differences between the two more often than not, so I know whatever the Libre says, I am probably to take 10% away.

    Will need to do some more tests on this, say if I reach 5.0mmol on the Libre, will I be in the early 4's etc
     
  10. Mark_1

    Mark_1 · Well-Known Member

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    You may find your meter is a lot more accurate than the 10% required. Mine is 2%. Check with the manufacturer they should have the figures. Not sure about the Libre.
     
  11. TheBigNewt

    TheBigNewt Type 1 · Well-Known Member

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    How much more is the Dexcom there? And I like that BT Blucon Nightrider app thingy. How much is 100 "quid" anyway, is that like a "buck"? And what the he*# is a "plaster" you stick it on with? I love your slang words!
     
  12. Scott-C

    Scott-C Type 1 · Well-Known Member

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    Yeah, pretty much - quid is slang for a British pound, like buck is slang for a dollar. Plaster is just a sticking plaster, what you guys maybe call a Band-Aid.

    Don't use dexcom so can't say what the cost is.

    I'll probably get around to trying dexcom sometime to compare the two setups but libre with blucon and xdrip+ is doing pretty much I want it to - keep an eye on when I'm going out of range and then pin it, and wake me up if I'm going hypo at 3 am after a few beers on a Saturday night. It can also be set up to alert parents and allow them to monitor from a distance but I've not looked into that. So, does what dexcom does. Some dexcommers use xDrip+ instead of the official dexcom app. It was initially developed by the Nightscout Foundation, a group of T1s and parents of and T1s who felt commercial apps weren't up to it, so it's got pedigree.
     
  13. JoeT1

    JoeT1 Type 1 · Well-Known Member

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  14. slip

    slip Type 1 · Well-Known Member

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    Joe - the Libre scan result number is a result of an algorithm which tends to over emphasises the highs and the lows, in between the 'normal' range it's pretty good especially for allowing the time difference, your results you've supplied are, how shall we put it.........higher than normal working parameters ;) - so will be subject to this over emphasise.

    I'd imagine once you get within the 'normal' range with this sensor you'd find the accuracy more in keeping with your expectations.

    And as for you're earlier picture of several scans over a short period but with differing results, the 'level' arrow indicator means your BG is stable or moving (in one direction or the other) at a slow(ish!) rate - it does give the rate of change criteria in the manual I think. It doesn't mean it's rock solid static. (if only we could achieve that!)

    bodily fluids and it's glucose content is always changing too.
     
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