The MHRA warning comes in light of a number of reports of adverse incidents.
It was found that the units of measurement displayed on the LifeScan Onetouch, LifeScan InDuo and LifeScan Pocketscan blood glucose meters changed from mmol/L to mg/dL.
The units of measure may change if the meter is dropped, or if the battery is changed when the meter is switched on.
There may also be some meters for which the units of measurement displayed can inadvertently be changed by the user.
The MHRA is concerned that this change in unit of measurement could lead users to think that the blood glucose result is high and that it may lead to an altered treatment regime.
A blood glucose test that is displayed in mg/dL will be 18 times higher than a blood glucose test expressed in mmol/L.
This could result in patients self-administrating an insulin overdose and going into a hyperglycaemic coma.
LifeScan is planning a comprehensive meter replacement programme with all users expected to be contacted in early 2007.
The MHRA advises that, in the meantime, users of the blood glucose meters ensure that the meter reads in mmol/L every time they test.