SAN DIEGO – Tandem Diabetes Care, Inc. (Nasdaq: TNDM) has announced a voluntary medical device correction for certain t:slim X2 insulin pumps due to a potential speaker-related malfunction that may disrupt insulin delivery.
The issue can trigger a “Malfunction 16” alarm, which stops insulin delivery and severs communication between the pump and its continuous glucose monitoring (CGM) system. This interruption could lead to hyperglycemia as users may no longer receive insulin, estimated glucose values, or trend data. In severe cases, medical intervention or hospitalization may be necessary.
To date, the company has confirmed 700 adverse events involving high blood sugar or incidents requiring medical attention. There have been 59 reported injuries linked to the malfunction. No deaths have been reported.
Tandem issued direct notifications to affected customers in the United States between July 22 and 24, 2025, outlining steps to take if a Malfunction 16 alarm occurs. The company has also provided a way for customers to verify if their pump is affected based on serial number.
Regulatory agencies, including the U.S. Food and Drug Administration and counterparts outside the U.S., have been notified of the correction.
To mitigate risk, Tandem plans to release a software update that will improve early detection of speaker issues and introduce persistent vibration alerts. Customers will be informed once the update is available and will be asked to install it to ensure continued safe use of their devices.
