Modifier 59 is the most abused modifier and the most watched modifier. The OIG recently published findings from an audit to determine if modifier 59 was being used appropriately. What they found is that 40 percent of claims did not meet program requirements to support modifier 59. Another 11 percent were found to have modifier 59 appended to an incorrect code. Consequently, the OIG is encouraging Medicare payers to conduct pre-payment and post-payment reviews. In this session we will discuss how to audit modifier 59 to reduce the risk of adverse findings in an external audit. We will look at procedure notes to determine whether modifier 59 is appropriate.