Key Takeaways
- First-listed outpatient diagnosis reflects the encounter focus after applying ICD-10-CM conventions.
- Procedure coding requires note-based validation of site, approach, and documented work.
- Modifier decisions are secondary to correct base code assignment and documentation fit.
Last updated: February 2026
Practical coding workflow
Use a fixed order for consistency:
- Identify the chief outpatient reason for service.
- Apply diagnosis conventions and sequencing rules.
- Assign CPT/HCPCS from completed documentation, not planned intent.
- Add modifiers only when policy and record evidence support distinct reporting.
This prevents common sequencing and modifier overuse errors.
Test Your Knowledge
In outpatient facility coding, what should happen before adding modifier 59 or X{EPSU}?
A
B
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D