Free style libre

The sensor reads interstitial fluid, so is 15 minutes behind finger prick tests. Some sensors are more accurate than others, but they generally are less accurate below 4 and above 10 as they are licensed for readings between 4-10. You may also find some sensors are consistently out by a certain amount. Not sure when you applied this sensor, but a lot of us put a new sensor on 24 hours before the previous one finishes to let it "soak", and the readings are generally more accurate from day one then.
Sensors are great for trends, some people give insulin with the readings, but others check with finger pricks, it all depends how accurate an individual sensor is as to how much I trust it. It's also worth noting blood glucose monitors only have to have an accuracy of +/- 15, so nothing is 100% accurate.

When did you put the sensor on?
They are renowned to be inaccurate for the first 24 to 48 hours.
I always put my sensor on one or two days before starting it.

The other thing to remember is that Libre is most accurate between 4 and 8 mmo/l. Outside this range, it is always advised to check with finger pricks before making any correction.

Finally, it is recommended to check your sensor at least once a day when your blood sugars are stable. Some sensors drift over time so you need to be aware of how close the finger pricks each sensor is.

Samanthav21 said:

Hello, recently I have decided to move my free style libre sensor onto my thigh, as I’ve seen many people try this and it give me the reading of 10.8, but when I check my levels by finger prick it reads 9.7! I have no idea what one to go by. Any ideas on what I should do? Why is my readings different and does it even matter if they are slightly different readings?

Click to expand...

Hi,

I'm an inside the arm person. I normally take a calibration test from a finger on the same arm as the placment of the sensor?
Alowing for a 15/20 minute lag.. The reasonably happy with it when within 0.6Mmol..

I’m on my 4th Libre now and have consistently found the average BG levels seem to rise in the last few days, by circa 10% versus the week 1 readings despite no change in diet/activity. Particularly the last 3-4 days of the 14 the readings seem increasingly implausible. Has anyone else noticed this?