When a separately reportable service has been performed and there is no HCPCS Level I (CPT, including Category I and Category III) codes or HCPCS Level II code which describes the service or procedure, an unlisted code is generally reported. In the CPT codebook the unlisted service/ procedure codes can be found at the end of a section or subsection. The long descriptors for these codes start with the term “Unlisted”. Unlisted codes should be reported only if no other specific HCPCS codes adequately describe the procedure or service.
Under the outpatient prospective payment system (OPPS), the Centers for Medicare & Medicaid Services (CMS) generally assigns the unlisted service or procedure codes to the lowest level APC.
For non-OPPS, when an unlisted service or procedure code is reported, a report describing the service or procedure should be submitted.
The latest list of “Unlisted” CPT codes for procedures and services can be found at http://www.cms.hhs.gov/HospitalOutpatientPPS/ under the category titled “Annual Policy files.”