Inaccurate sensor readings

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Chris27

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Type 1.5 LADA
Is anyone else, like me, suffering from increasingly inaccurate readings from their Libre sensor? My current reading from my new sensor (after breakfast) is 12.1 against a prick test of 9.5. The previous one regularly showed readings between 1 and 2 higher than the prick test. The one before that was giving such low readings that my low glucose alarm was triggered (falsely) several times a day, and I had to abandon it. Is there any explanation? What can I do about it? This is after quite a run of accurate sensors, but now I feel I can scarcely rely on it.
 
Abbott will probably replace it.

They generally want it to have been 'on' for over 24 hours and have 3 comparison readings.
 
I get the feeling abbotts quality control has gone downhill. Time to give dexcom a try?
 
@Chris27 whilst some people do find Dexcom suit them better, it is first important to understand the limitations of all CGMs.
For a start, the accuracy is a percentage not an absolute so higher n7mbers are likely to vary by more. The required standard for all blood glucose meters is +/- 15%. The example you gave with your current sensor is within 15%. If your “real” reading was 10.5, an acceptable reading from either meter could be anywhere between 8.9 and 12.1.

There are other limitations of CGMs which are outlined in this post https://forum.diabetes.org.uk/boards/threads/cgm-limitations-and-precautions.108188/

It is easy to feel that Libre quality is not up to scratch because there are more complaints than with Dexcom. But, far far more people use Libre and it is human nature to complain rather than express delight.
I have tried a number of different CGMs and had more issues with Dexcom.
I use a different CGM now but only because it interacts with my insulin pump. If I could not afford to self fund, I would happily continue with Libre 2.
 
How long after breakfast did you test? If your levels are changing direction or their rate of change is changing then Libre will be out by more. I only ever do comparisons with a finger prick when my levels have been stable mid range for at least half an hour and there is little or no food or bolus insulin impacting them. If your levels are changing fast and then leveling out or completely changing direction, Libre will take about half an hour to catch up with that change and in the meantime they will likely be much further out, but the graph will correct itself, even though you may have a reading in the log which the graph no longer goes through. You wouldn't base any decisions on Libre at those times because either food or bolus insulin would be working or if you were hypo, you should be using a finger prick to track your hypo recovery anyway.

Understanding the limitations of Libre is really important to get the best out of it.
 
Chris27 said:
Is anyone else, like me, suffering from increasingly inaccurate readings from their Libre sensor? My current reading from my new sensor (after breakfast) is 12.1 against a prick test of 9.5. The previous one regularly showed readings between 1 and 2 higher than the prick test. The one before that was giving such low readings that my low glucose alarm was triggered (falsely) several times a day, and I had to abandon it. Is there any explanation? What can I do about it? This is after quite a run of accurate sensors, but now I feel I can scarcely rely on it.
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If your levels are changing quickly those readings are reasonable, as there is a time lag between the sensor reading and the BG, although I realise that the Libre algorithm takes some account of this. The quicker your levels are changing the beignet difference you will get.
If it is a long way out consistently they will replace the sensor.
 
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