As in readings or symptoms?
It is not unusual for healthy people to drop under 4 mmol/L as part of the body's normal fluctuations. And so that can also happen to people who take Metformin too. But while such levels are technically defined to be hypoglycaemia, that does not necessarily make them clinically relevant. It is mainly only those who take insulin or a medication like Gliclazide that need to take them seriously, because of the risk of them continuing to fall.
And the usual caveat applies to the accuracy of glucometers. everydayupsanddowns has been recently posting a table with examples of this, noting that there is a ±0.83 mmol/L margin of error allowed under 5.6 mmol/L.
So the original reading of 3.8 may not have been a hypo at all. Admittedly the real level could also have been under 3 mmol/L, but that is unlikely unless there is another medical complication. And at those level it should be the symptoms that alert you to it rather than a routine test.
But a reading of 4.5 is within every definition of the normal range, and it could represent levels as high as 5.3 mmol/L. So it should not need treating as though it means there is an impending hypo. If it does mean that then there is another problem which need attention.
