Patients are being warned to stop using some glucose monitors made by Abbott Diabetes Care after the company found malfunctioning sensors may be linked to hundreds of adverse events and several deaths, the Food and Drug Administration said Tuesday. 

Internal testing by Abbott found that some sensors in certain FreeStyle Libre 3 and FreeStyle Libre 3 Plus devices may provide incorrect low glucose readings, the company said in a news release. Abbott said it had received reports of 736 adverse events potentially linked to the issue. Fifty-seven were reported in the United States. Seven deaths, none of which were in U.S., were potentially associated with the sensor error, Abbott said. The FDA referred to the error as a “potentially high-risk issue” in a news release. 

People with diabetes depend on glucose readings to manage their care. Incorrect low readings can lead to excessive carbohydrate intake or skipped or delayed insulin doses, Abbott said. Those decisions “may pose serious health risks, including potential injury or death,” the company said. 

The sensor issue was related to one production line among the several that make the Libre 3 and Libre 3 Plus sensors, Abbott said. About three million devices are affected, about half of which are estimated to have expired or been used. 

Anyone using a Libre 3 or Libre 3 Plus sensor should check its model number and unique device identifiers to see if it is one of the affected devices, the FDA and Abbott said.  

The model numbers for the affected FreeStyle Libre 3 sensors are 72081-01 and 72080-01, and the unique device identifiers are 00357599818005 and 00357599819002. The model numbers for the affected FreeStyle Libre 3 sensors are 78768-01 and 78769-01, and the unique device identifiers are 00357599844011 and 00357599843014. The full list of affected lots is available on the FDA’s website. 

Anyone with an impacted device should stop using it, Abbott and the FDA said. Patients can request free replacement devices on www.FreeStyleCheck.com, Abbott said. Patients should use a blood glucose meter or the built-in meter on a FreeStyle Libre 3 Reader to make treatment decisions when sensor readings don’t match symptoms or expectations, Abbott said. 

Abbott and the FDA said that FreeStyle Libre 3 readers and mobile apps have not been impacted, and that no other Libre-brand sensors are affected by the sensor issue. The cause of the sensor issue has been identified and resolved, Abbott said, and no supply disruptions are expected.