M12 vs M67.3
M12 and M67.3 can never be reported together. ICD-10-CM declares them mutually exclusive with an Excludes1 note, meaning the two conditions cannot occur in the same patient — so exactly one of them is correct for any given encounter.
The official note, declared on M67.3
palindromic rheumatism (M12.3-)
M12
Other and unspecified arthropathy
Not billable
- Chapter 13
- Diseases of the musculoskeletal system and connective tissue
- Section
- M05-M14
M67.3
Transient synovitis
Not billable
- Chapter 13
- Diseases of the musculoskeletal system and connective tissue
- Section
- M65-M67
Use when the record says
- Toxic synovitis
Indexed under
- Synovitis › transient
Excludes1 is not always absolute: where two conditions covered by the note are genuinely unrelated, CMS guidance permits reporting both. Document the reasoning rather than assuming it. More on Excludes1 vs Excludes2 · FY2027