Source: Emily Hill, PA, AAPM Coding Consultant
Date: January 24, 2018

CMS has released a revised article that addresses the appropriate reporting of bilateral procedures and the potential impact of its rules known as “medically unlikely edits” (MUE) on reimbursement. The revised article provides more examples and details.

Bilateral procedures are those that are performed on paired organs or body structures. The use of the bilateral modifier 50 depends on the code descriptor and the bilateral “indicator” assigned by CMS. These indicators determine if reimbursement will be adjusted and paid at 150% of the Physician Fee Schedule (PFS) rate for the code. A bilateral payment indicator of 1 results in a payment adjustment. Codes assigned an indicator of 0, 2, or 3 will not result in a bilateral payment adjustment. When appropriate to append modifier 50, Medicare instructs that the CPT code be reported with modifier 50 as a single line on the claim and with 1 unit of service.

A MUE is the maximum number of units that can be reported for a particular CPT code by the same provider for the same patient on the same date of service. The MUEs are based on claims history and input from specialty societies on common clinical practice. MUEs may limit the number of units that can be reported with certain CPT codes. The reporting of bilateral procedures on more than one claim line or with more than one unit of service may exceed the number of allowed units and result in denials. It is therefore important to follow Medicare’s instructions when reporting bilateral procedures.

The bilateral indicators for CPT codes can be found in the PFS Relative Value Files.

The recently revised AAPM coding and reimbursement tool, Common Pain Medicine Codes (login required), also denotes which codes allow modifier 50.