Freestyle libre overnight readings.

[Wurst]

Quick question can you set up your Libre to read overnight autonomously? I had to buy my meter separately (off ebay) as the health insurance wouldn't pay for it and I ended up with a non English version.

I've worked everything else out but can't figure out the overnight readings, if this is even possible.

 

[tim2000s]

Quick question can you set up your Libre to read overnight autonomously? I had to buy my meter separately (off ebay) as the health insurance wouldn't pay for it and I ended up with a non English version.

I've worked everything else out but can't figure out the overnight readings, if this is even possible.

The Libre sensor records data all the time, and stores up to eight hours of it, then when you scan it downloads everething it has captured.

So overnight you are fine, as long as you sleep for fewer than 8 hours.

 

[Wurst]

The Libre sensor records data all the time, and stores up to eight hours of it, then when you scan it downloads everething it has captured.

So overnight you are fine, as long as you sleep for fewer than 8 hours.

Thanks for the explanation and that explains the gap in the data i'm seeing.

 

[tim2000s]

Thanks for the explanation and that explains the gap in the data i'm seeing.

Have to admit that's not something I've seen. It may be worth a call to Abbott.

 

[Snapsy]

The sensor needs to be scanned at least once every 8 hours, @Wurst , as it can only hold 8 hours' worth of data.

Last time I went to bed early and didn't scan in the night, my reader showed an overnight gap in the morning where data had 'dropped off' in the interim.

 

[Wurst]

My last scan was at ~ 20:30 and I got up and scanned again at ~06:40. The gap was between ~20:30 and ~22:30, so it appears to drop the older data.

One other thing , I've been using it for 24 hours and I'm continually getting low readings. I've calibrated it with my glucose readers and it appears to be around 20 mg/dl out (too low). Is this normal given it is measuring interstitial versus blood glucose or is it still bedding in ?

I've read the accuracy can be off for up to 48 hours after activating the sensor.

 

[tim2000s]

The sensors do seem to take longer to settle than the Dexcom ones, and many people leave them in for 24 hours before activating them. If you're still seeing bad numbers after three days of having had it attached, then it's worth contacting Abbott about it.

 

[Wurst]

Not very sure what you mean by calibrating the sensor.

A very simple calibration by comparing the finger prick glucose reader values against the libre values. I trust the glucose reader values unequivocally (One touch verio) and have based my tight control on their outputs for the last 5 years. If I know it's going to be 20 mg/dl ~ 1.1 mmol out continuously then I can adjust accordingly.

 

[Snapsy]

@Wurst my own Libre reader reads lower than my blood readings, pretty consistently. It doesn't bother me though as I use it for the graph line and for the trend arrows, albeit to a lesser extent.

 

[Notorious]

Low readings overnight can be because you were lying on the sensor, by the way. Not necessarily a nocturnal hypo.

 

[Robbity]

I've seen these gaps both during the day as well as overnight if I don't scan at least every 8 hours. if you go longer between scans, since the sensor can only hold 8 hours worth of data it will overwrite the earliest stuff and this shows up as gaps in your graphs. And the size of the gaps will obviously correspond to the length of time over the 8 hours there was between the scans. (It's not a fault - it's a feature! )

I've also found (and thanks to other Libre users for this info) that unless I leave a new sensor to sit on my arm to acclimatize for around 48 hours before activating, it will definitely give me really scarily low lows, particularly overnight, and if I happen to lie on my sensor arm. Giving it the settle in time more or less completely avoids this for me.

Immediate activation:

Delayed activation (approx 48 hours):

And like @Snapsy, my sensors have consistently read 1-1.5 points lower than finger pricks, but as a T2, I'm really more interested in patterns/trends and these tend to match my meter results pretty consistently - but obviously in much greater detail.

Robbity

 

[Wurst]

Thanks for all the info, most useful. Today's readings are marginally closer to my glucose reader's ~ 0.5 mmol on the low side.

Might take some time to fully 'trust' it due to the dispersion of results, especially when it comes to bolusing.