The OIG has released a report summarizing state fraud and abuse safeguard activities related to Medicaid NEMT. According to the OIG, such safeguard activities include screening providers, requiring prior approval for services, and other methods to prevent and detect improper payments. OIG also found that state Medicaid fraud control units investigated a total of 509 NEMT fraud and abuse cases from 2004 to 2006, with the most common types involving billing for services not rendered, unspecified overbilling, and upcoding.