The FDA is letting a swath of app developers off the hook with its final rules regarding medical applications for mobile platforms.

The federal watchdog agency said that it’s going to focus its review and regulatory efforts on a small subset of applications that it deems risky enough to harm patients if not working as intended. That means the majority of healthcare apps won’t be regulated under the FDA’s charter as the agency deems them of minimal risk to consumers.

The agency’s "tailored" approach is similar to what had been proposed in draft guidance in 2011, largely bypassing apps that are used solely to log or record information, ones that automate administrative duties like billing or inventory and programs that provide "copies" of medical texts.

Apps that will get more attention include those that are developed as an "accessory" to a regulated device, ones that help healthcare providers view images for analysis and diagnosis and devices that effectively "transform" a mobile device into a medical device, such as smartphone-based heart rhythm monitors.

Apps that fall under the FDA’s more stringent purview will get the same regulatory treatment as any other device in their class, according to the newly released rule.

The FDA has slowly been making progress toward clarifying what it expects from mobile health application developers, including last month’s new medical device interoperability standards, which help make the path to 510(k) clearance a bit easier for devices that exchange data.

Some mobile health app developers have felt stymied by the FDA’s long-delayed guidelines, but that hasn’t stopped the market from booming. There were already some 40,000 health-related mobile apps globally by this time last year, according to the Assn. of American Medical Colleges.