For many in the software world, medical apps have been a controversial topic, either hailed as the future of medicine or tarred as snake oil. But this week, the FDA weighed in, handing down official guidelines on how it would approach the growing sector. The result stays close to the draft guidelines the agency handed down in 2011, looking only at apps that would "transform a mobile platform into a regulated medical device," and then evaluating those apps for potential harm to patients.

"People still need a sense of which apps they can rely on."

The report singled out apps that display medical data directly from a device, whether it's a blood pressure reading or the previously stored EEG waveforms from a patient's brain. Even if the app is only serving as a display monitor for the data, it would qualify as a medical device, requiring developers to go through the same FDA channels as their competitors. One example given by the guidelines is an app that uses a phone's accelerometer and microphone to measure movement during sleep, put to work as a treatment for sleep apnea. Since the app competes against existing sleep apnea treatments, it will have to face the same federal scrutiny. Non-medical apps will still be able to transmit pre-reported medical information, but anything involving direct diagnostic data will come under the FDA's scrutiny.

In general, it's good news for medical app-makers, which finally have a firm sense of when they'll have to navigate FDA regulation. But while the FDA is set to rule out explicitly harmful apps, it leaves room for apps that are below reasonable standards or shoddy in more subtle ways. "Where's the consumer reports for medical apps? That's what we're missing now,"  says Daniel Schwartz, medical director at QxMD Software. "People still need a sense of which apps they can rely on, and the FDA is not set up to provide that."