Loading ...

Tandem Diabetes Care has sent an “Urgent Medical Device Correction” letter to potentially affected users of the t:slim X2 insulin pump, cautioning that the pump’s speaker could fail, causing insulin delivery to stop. 

Certain versions of the pump’s speaker were found to have a wiring issue that leads to higher than usual rates of a specific type of malfunction (“Malfunction 16”). That, in turn, causes the pump to stop delivering insulin and terminates communication between the pump and the continuous glucose monitor, as well as the t:slim mobile app. If not addressed, severe hyperglycemia could result. 

As of July 22, 2025, the date of the letter, there had been 700 reports of adverse events and 59 reported injuries but no deaths. 

A medical device “correction” is the FDA’s term for a repair, modification, adjustment, relabeling, or inspection of a product without its physical removal. 

Tandem said that it will be releasing a software update that will enable early detection of speaker failure and will issue persistent vibration alerts to notify patients of potential safety risks. The company will alert users when the update is available and guide them through the process. 

In the meantime, patients who receive the Malfunction 16 alert should acknowledge it by pressing “Silence Alarm,” call or email Tandem at Techsupport@tandemdiabetes.com, switch to backup methods of insulin delivery and glucose monitoring, and monitor blood glucose frequently. 

Those who haven’t received the Malfunction 16 alert should continue using their pumps as usual but should make sure that their Tandem t:slim mobile apps are turned on with push notifications enabled in case the malfunction does occur. Those using Dexcom sensors should use the Dexcom mobile app as a secondary alert system. 

Patients who received the letter but not the malfunction alert can check here to see if their pump’s serial number is on the affected list.

Miriam E. Tucker is a freelance journalist based in the Washington DC area. She is a regular contributor to Medscape Medical News, with other work appearing in the Washington Post, NPR’s Shots blog, and Diatribe. She is on X @MiriamETucker and BlueSky @miriametucker.bsky.social.