Section F · FY 2026

Selection of Principal Procedure

F Selection of Principal Procedure #

The following instructions should be applied in the selection of principal procedure and clarification on the importance of the relation to the principal diagnosis when more than one procedure is performed:

F1 Procedure performed for definitive treatment of both principal diagnosis and secondary diagnosis #

  • a. Sequence procedure performed for definitive treatment most related to principal diagnosis as principal procedure.

F2 Procedure performed for definitive treatment and diagnostic procedures performed for both principal diagnosis and secondary diagnosis. #

  • a. Sequence procedure performed for definitive treatment most related to principal diagnosis as principal procedure

F3 A diagnostic procedure was performed for the principal diagnosis and a procedure is performed for definitive treatment of a secondary diagnosis. #

  • a. Sequence diagnostic procedure as principal procedure, since the procedure most related to the principal diagnosis takes precedence.

F4 No procedures performed that are related to principal diagnosis; procedures performed for definitive treatment and diagnostic procedures were performed for secondary diagnosis #

  • a. Sequence procedure performed for definitive treatment of secondary diagnosis as principal procedure, since there are no procedures (definitive or nondefinitive treatment) related to principal diagnosis.
Source: ICD-10-PCS Official Guidelines for Coding and Reporting, FY 2026 from CMS, effective October 1, 2025 through September 30, 2026. We publish the guideline text as CMS wrote it and add the code links and navigation.