Yes at times the Libre I had were fine, then would get 2 in a row not working well from same lot and expiry date, had to replace them twice in the same month. Also the first 24 to 48 hrs it may not be accurate either. I did like using the Libre as it really helped me understand what foods did to my sugar. So if on day 2 and 3 I get the same difference number with each test compared to the blood value, I would add that number to all blood results the device would give me. Also when your sugar levels are fluctuating quickly the device as explained to me by the company can have up to 20 min delay in results, so poke once then scan every 5 min for 20 min and it should be close to your true blood value by then. Sometimes they are accurate and most time there is a difference but usually the difference is always quite constant so you can add or substract from the readings you get. It can take up to 1 or 2 weeks at times to get a replacement.

There does seem to be a decent percentage of "bad sensors" with both the Dexcom and the Libre system.

The technology is still pretty new so you have to expect some "bugs in the process", but all in all I think they are an awesome resource that eventually will do great things to the management of Diabetes.

With dexcom there will be a slight difference in numbers, about a 20% difference. If it’s a bigger gap, you can calibrate it. Also if you test your blood sugars, wait about 10-15 minutes then check dexcom it’ll be way closer (within the 20% allowable range). I switched from freestyle libre to dexcom, have done that and numbers are extremely close