Header: As we prepare for the September AMA CPT meeting in Minneapolis, one proposal brings new "Appendix S" strongly into the Category I, Category III Code Change Application (MSP Tab 94). But "Appendix S" has major flaws as a classification architecture, and it should be fixed before importing it any further into CPT operations. A new 10-page white paper explains it all.
SUMMARY
AMA's 2027 Appendix S is an important attempt to create stable terminology for software-enabled CPT services, but its three familiar categories remain logically unstable because they combine several different classification axes.
This paper shows why even a simple
three-question decision tree fails under the present definitions, then proposes
a clean-sheet replacement: neutral Class I, Class II, and Class III categories
built from exclusive rules and validated empirically before publication.
- Why Appendix S Matters
- What the 2027 Revision Gets Right
- The Central Design Problem: Vocabulary Came Before Logic
- What a CPT Taxonomy Must Be Able to Do
- The Minimalist Three-Question Test
- Why the Minimalist Matrix Fails Under the Current Appendix S
- The Failure Reveals the Real Problem: Multiple Classification Axes
- Case Study: A Molecular Test at the CPT Deadline
- The MAAA Problem: Development Method Is Not Runtime Function
- The Lower Boundary: Risk, Scores, and Mathematical Simplicity
- The Highest Boundary: Radiology, Laboratory Medicine, and Final Results
- Why the Current Experience Argues for a Clean-Sheet Numbered System
- Proposed New Taxonomy: Class I, Class II, Class III
- A Minimal Decision Procedure for the New System
- Keep Human-Control Architecture Separate from the Three Classes
- Validate the Taxonomy Empirically Before Publication
- Conclusion: From Negotiated Vocabulary to a Tested Classification System
