Dodgy data using FreeStyle Libre 2+?

Were you asleep and lying on the Libre when it reported the low? I don’t know if you are aware of compression lows, caused by squashing the sensor. I’m just switching from Libre 2 plus to Dexcom One + purely because I self fund and Dexcom’s subscription will work out much cheaper for me. I was actually quite happy with the Libre 2 plus.

X2 on positioning the sensor where you can't lie on it.
The sensor app does have a habit of changing its mind and rewriting the blood sugar graph history, sometimes by quite a margin.
Handy, when you have eaten carbs to sort a "hypo", then finding ten minutes later that the app has rewritten the last 30 minutes as 2mmol higher.
Not to knock them too much, but I don't think the app developers talked to many actual diabetics when creating the app.

Improvements?
1...Different alarms for high & low,
it would be much safer for driving without having to prat about with your phone trying to find out if high or low.
2...Stop hiding behind the "Sensor Error" message.
Instead give a warning that it might be wrong & provide the data that the app is doubting. For exercise, I cycle, from the back door, there is 1000 feet of climbing at 20% to get my 14 stones onto Dartmoor. As I go up, the blood sugar goes down. Not once has the app kept up without hiding behind the "sensor error" message.

I came here specifically to ask about this. I've been on CGM Libre FS2 for a few months now, and I thought it was reading lower than it should. Last month, I was in hospital, and they were doing hourly and then 2-hourly blood tests, so I would check my phone each time to see if it was the same. It was consistently lower than th blood tests shown - the smallest discrepency was 0.6 lower, with 4.1 blood test and 3.5 on the sensor, but it was also up to 2.2 lower at higher levels - 11.5 on the blood test and 9.3 on the sensor. I've recently had an HBA1C done, and the sensor said it should be 44, but the actual result is 52mmol. Is there a way to recalibrate them, or is this sort of gap normal and the rest of you just mentally adjust because you know it will read low? Thanks for any help.

SusanSays said:

I came here specifically to ask about this. I've been on CGM Libre FS2 for a few months now, and I thought it was reading lower than it should. Last month, I was in hospital, and they were doing hourly and then 2-hourly blood tests, so I would check my phone each time to see if it was the same. It was consistently lower than th blood tests shown - the smallest discrepency was 0.6 lower, with 4.1 blood test and 3.5 on the sensor, but it was also up to 2.2 lower at higher levels - 11.5 on the blood test and 9.3 on the sensor. I've recently had an HBA1C done, and the sensor said it should be 44, but the actual result is 52mmol. Is there a way to recalibrate them, or is this sort of gap normal and the rest of you just mentally adjust because you know it will read low? Thanks for any help.

Click to expand...

thats within acceptable params. 52mmol/mol Libre2plus mard = 8.2% so between 47.736 and 56.264 is considered acceptable.

their is 3rd party apps which you can calibrate, however caveat with doing so it can increase error especially if glucose levels were changing at the time they were calibrated. It also measures interestrial fluid which speed of movement can change with pressure and indeed temperature. abbotts choose what they consider average ranges and test on that. they are normally slightly more accurate when well hydrated. if your still wishing to calibrate look up the likes of xdrip+ if using an android phone.

edit added below:
there is also roughly 10-15 minute delay between interestrial fluid and actual blood glucose so you have also got to take that into account especially if bg is moving up / down at all.

grantg said:

thats within acceptable params. 52mmol/mol Libre2plus mard = 8.2% so between 47.736 and 56.264 is considered acceptable.

their is 3rd party apps which you can calibrate, however caveat with doing so it can increase error especially if glucose levels were changing at the time they were calibrated. It also measures interestrial fluid which speed of movement can change with pressure and indeed temperature. abbotts choose what they consider average ranges and test on that. they are normally slightly more accurate when well hydrated. if your still wishing to calibrate look up the likes of xdrip+ if using an android phone.

edit added below:
there is also roughly 10-15 minute delay between interestrial fluid and actual blood glucose so you have also got to take that into account especially if bg is moving up / down at all.

Click to expand...

Thank you very much - I knew about the time lag, but you've eased my mind about the differences - I'll just remember to take them into account

@Lazelle I agree about different sounds for highs and lows. These days if I am travelling on my own some distance I always switch the high alarm off so that if it were to go off I would know I needed to take action. Have to remember to switch back on though.

Occasional problems, but I think they err on the side of safety.
I don't need the high alarms on, just keep an eye on things. I turn the low alarm off at night too, where the omnipod excels.