M06.1 vs M08
M06.1 and M08 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 M06.1
Still's disease NOS (M08.2-)
M06.1
Adult-onset Still's disease
Billable
- Chapter 13
- Diseases of the musculoskeletal system and connective tissue
- Section
- M05-M14
Indexed under
- Still's disease or syndrome › adult-onset (juvenile)
M08
Juvenile arthritis
Not billable
- Chapter 13
- Diseases of the musculoskeletal system and connective tissue
- Section
- M05-M14
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