The OIG has identified 20 portable x-ray suppliers — entities that furnish x-rays at a beneficiary’s location using mobile diagnostic equipment — with questionable billing patterns in 2008 and 2009. For instance, OIG found that while portable x-rays (unlike other tests) must be ordered only by a licensed physician, they discovered that Medicare paid approximately $6.6 million for such services ordered by nonphysicians such as physician assistants and nurse practitioners (who can order tests in other non-hospital settings). The OIG also identified questionable billing related to return trips to nursing facilities.  In the report, “Questionable Billing Patterns of Portable X-Ray Suppliers,” the OIG recommends that CMS take a series of steps to improve oversight of portable x-ray suppliers, including collecting identified overpayments, establishing a process to periodically identify portable x-ray suppliers that merit greater scrutiny, and establishing controls to limit payment to only portable x-ray services ordered by physicians. CMS concurred with the OIG’s recommendations.