CMS has issued a transmittal to further clarify CMS policies requiring physician supervision of diagnostic and therapeutic services provided to hospital outpatients. In this update, CMS is clarifying policies regarding supervision of diagnostic tests by non-physician practitioners, and CMS further defines the term immediately available and clarifies the credentials, knowledge, skills, ability, and privileges that the supervisory practitioner must possess in order to be qualified to perform a given service or procedure. Note that the transmittal includes more restrictive language than the final 2010 hospital outpatient PPS rule with regard to the qualifications of the supervising physician of a diagnostic test and the proximity standard for the physician providing direct supervision of a diagnostic test. The transmittal is effective July 1, 2010. CMS has also released a related educational article about the policy.