In February 2015, the FDA published a guidance stating that it plans to regulate mobile health apps based on their functionality, rather than their sale. The guidance announces the FDA’s intention to regulate certain mobile medical apps used by doctors to diagnose and monitor patient health as medical devices.

Specifically, the guidance notes that the FDA will focus its oversight on mobile apps that are either meant to be used as an accessory to a regulated medical device or are intended to transform a mobile platform into a regulated device. Pursuant to the guidance "if a mobile app is intended for use in performing a medical function (i.e., for diagnosis of disease) it is a medical device [subject to FDA regulation], regardless of the platform on which it is run."

Furthermore, the FDA’s oversight applies to mobile apps performing medical device functions, the functionality of which could pose a risk to a patient’s safety if the mobile app were not to function as intended (e.g. mobile apps that control infusion pumps, calibrate hearing aids, etc.).