Tandem Diabetes Issues Correction for Certain t:slim X2 Insulin Pumps

Tandem Diabetes Care announced a voluntary medical device correction for select t:slim X2 insulin pumps to address a possible speaker-related issue that can cause an error resulting in discontinuation of insulin delivery.

The error appears as a Malfunction 16 alarm to the user. It will stop insulin delivery and cease communication between the pump and continuous glucose monitoring (CGM) device.

If left unaddressed, this could cause hyperglycemia due to the discontinuation of insulin delivery, real-time CGM estimated glucose values, and CGM trends. In severe hyperglycemia cases, the user may need hospitalization of intervention.

There have been 700 confirmed adverse events and 59 reported injuries. No deaths have been reported.

Notices were sent to impacted U.S. customers were sent between July 22 and 24, 2025 with instructions about the steps to take in the event of a Malfunction 16.

Tandem said it will release a software update to boost early detection of speaker failure. The update will also introduce persistent vibration alerts to help reduce possible safety risk. The company will notify all pump users when the software update is available and request they complete the update of their t:slim X2 insulin pump.

More information, including a searchable list of serial numbers for impacted pumps can be found here.