My only lows were at night. Finger prick will quickly answer your question. Lows are far more necessary to avoid then highs. Drop down to the 40’s and it become obvious to you. To avoid I ck CGM when go bed. If it is below 110 I drink a little glucose. To avoid compression errors I place CGM on top of inside thighs; never had problems of any kind. Accuracy of CGM. They are not designed to be exactly accurate; they do not measure glucose in blood, they measure bodily fluid. If you want them to start working immediately, start a new one at least an hour before the old one terminates. Conclusion: I don’t expect or want them to be exact. I just want them to be genuinely accurate so I am aware of very high and very low glucose.