The Centers for Medicare and Medicaid Services (CMS) and its prescription drug plan sponsors "have not adequately performed one of the most basic oversight checks in Medicare Part D--ensuring that a drug was prescribed by a physician," said Robert Vito, acting assistant inspector general for CMS audits in the Office of Inspector General (OIG) at the U.S. Department of Health and Human Services, in congressional testimony last week. In 2007, $1.2 billion in Part D claims didn't include valid prescriber identifiers, according to an OIG report. "Without a valid prescriber identifier, CMS and its contractors cannot determine if a physician even prescribed a drug, much less verify that the physician was appropriately licensed or had not been excluded from the Medicare program," Vito pointed out. Since 2007, CMS has implemented national provider identifiers (NPIs) as the standard prescription identifier on Part D claims--a move that the agency says has improved the validity of prescription identifiers. But the OIG doesn't think that NPIs are a cure-all, cautioned Vito. Testimony