Medtronic is telling patients that certain lots of its infusion sets for its insulin pumps are being recalled as part of a voluntary effort.

The problematic infusion sets, which patients can identify by checking REF and LOT numbers on the available site, have a vent membrane that may be more likely to get blocked, possibly leading to too-high levels of insulin being delivered. This could endanger the patient and potentially cause hypoglycemia.

The vulnerable vent membrane was discontinued in April 2017, so infusion sets manufactured since then include an updated component and do not fall under this voluntary recall. Patients returning recalled sets will receive updated replacement sets for free.

“Our priority is to work with our patients to mitigate risk to patient safety. While we have shipped a significant number of the new and enhanced sets since April, we are committed to replacing recalled infusion sets for all patients,” Francine Kaufman, MD, chief medical officer of the Diabetes Group at Medtronic, said in an FDA safety alert. “Our Medtronic Diabetes team will work as quickly as possible to complete all exchanges to the new and enhanced set and fully support our customers throughout this process.”

Medtronic also stated that the voluntary recall is not expected to affect earnings per share guidance or Diabetes Group revenue growth for the current quarter—the second quarter of the company’s 2018 fiscal year—or the full fiscal year.

The voluntary recall comes as patients are clamoring for Medtronic’s diabetes devices. On the company’s earnings call in August, CEO Omar Ishrak explained that high demand for the company’s sensors, using in its insulin pump systems, had exceeded supply. There is also strong patient appetite for the new Medtronic MiniMed 670G insulin pump system, which offers a hybrid closed-loop system for insulin delivery.