With the explosion of apps that do everything from help people control their blood glucose levels to act like a stethoscope, the US Food and Drug Administration issued a draft guidance on how it will oversee such apps for smartphones or other mobile devices. "Our draft approach calls for oversight of only those mobile medical apps that present the greatest risk to patients when they don't work as intended," says Jeffrey Shuren, director of the FDA's Center for Devices and Radiological Health in a statement. The draft guidance seeks to clarify which apps the agency will regulate and particularly cites apps that are an accessory to a medical device (like allowing the user to read an X-ray on a smartphone), that transform smartphone or mobile device into a medical device (such as by allowing the user to detect heart patterns), or that give the user patient-specific information using an algorithm or formula as needing oversight. The agency notes that it has already cleared a few apps for health care providers to use in their iPhones and iPads.