British authorities said on Friday they had identified a safety problem with certain blood glucose meters, which could prompt patients to take an insulin overdose.

The issue relates to the FreeStyle, FreeStyle Mini and MediSense Optium Xceed devices made by Abbott Diabetes Care, as well as the LifeScan OneTouch, LifeScan InDuo and LifeScan PocketScan meters from LifeScan.

Lifescan is a unit of Johnson & Johnson.

The Medicines and Healthcare products Regulatory Agency said it had received reports that the units of measurement displayed on the meters could accidentally change. This could lead users to think their glucose levels were too high and self-administer an insulin overdose, potentially resulting in a coma.

The companies and the U.S. Food and Drug Administration warned of similar problems with certain glucose meters last year.