ROCHESTER - Calls made on cell phones do not affect hospital medical devices, U.S. researchers published in the March issue of Mayo Clinic Proceedings.

Tests at the Mayo Clinic in Rochester, Minnesota showed normal use of cell phones, also called mobile phones, caused no noticeable interference with patient care equipment, they said.

Most hospitals forbid the use of cell phones.

Dr. David Hayes and colleagues said their tests suggest the ban is unmerited. They tested cell phones using two different technologies from different carriers, switching them on near 192 different medical devices.

Three hundred tests were performed over a five-month period in 2006 and not a single problem occurred.

The authors say their trial and two earlier studies prove that cell phones will not interfere with the operation of lifesaving medical equipment and hospitals should reverse their current policies that ban the phones from most hospital campuses.

The study also contains two reports detailing which technological devices do cause patient care equipment to malfunction.