Modifier XS
Separate structure — a service distinct because it was performed on a separate organ/structure
✅ When to Use Modifier XS
When the same procedure is performed on a different anatomic structure (e.g., different joint, different organ).
📋 Documentation Requirements
Document the different anatomic site/structure.
Modifier XS FAQ
What does modifier XS mean? +
Separate structure — a service distinct because it was performed on a separate organ/structure
When should I use modifier XS? +
When the same procedure is performed on a different anatomic structure (e.g., different joint, different organ).
When should I NOT use modifier XS? +
Avoid appending this modifier if the documentation does not support its use.
What documentation is required for modifier XS? +
Document the different anatomic site/structure.
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Reviewed by the PayerReady Medical Coding Team
Verified against the CMS 2026 code set on July 16, 2026.
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