Contrary to common assumptions, cell phones don't interfere with medical device functioning, according to a study published in Mayo Clinic Proceedings. Two cell phones from different carriers were tested in various patient-care areas between February and June 2006. During 300 tests involving 192 medical devices in 75 patient rooms, researchers found no interference of any kind. They concluded that "when cellular telephones are used in a normal way, no noticeable interference or interactions occurred with the medical devices." They encourage hospitals to modify or abandon policies banning cell phone use in hospitals, which are a considerable inconvenience to patients and their families.