The 2008 Medicare Physician Fee Schedule makes significant revisions to the rules regarding purchased diagnostic tests and interpretations. These anti-markup rules are very poorly written but it appears the changes may affect the way physicians bill for diagnostic tests even if the diagnostic equipment is wholly owned by the physician group. The rules prohibit marking up tests or interpretations when they are performed "at a site other than the office of the billing physician." We will discuss the implications of this change on diagnostic tests performed by groups alone, or as part of a joint venture. We will also cover some of the other new rules in the 2008 fee schedule, including changes to the Independent Diagnostic Testing Facility (IDTF) rules and changes to the Compendia used to determine appropriate off-label use of drugs and biologicals for chemotherapy.