Excludes1 pair
M30.8 vs M35.1
M30.8 and M35.1 are not coded together. ICD-10-CM declares them mutually exclusive with an Excludes1 note — the two conditions are not expected to occur together, so exactly one of them is normally correct for a given encounter. The Official Guidelines carve out one exception: if the two conditions are clearly unrelated to each other, both may be reported.
The official note, declared on M35.1
polyangiitis overlap syndrome (M30.8)
M30.8
Other conditions related to polyarteritis nodosa
Billable
- Chapter 13
- Diseases of the musculoskeletal system and connective tissue
- Section
- M30-M36
Use when the record says
- Polyangiitis overlap syndrome
Indexed under
- Polyangiitis › overlap syndrome
- Syndrome › polyangiitis overlap
- Polyarteritis › nodosa › related condition NEC
M35.1
Other overlap syndromes
Billable
- Chapter 13
- Diseases of the musculoskeletal system and connective tissue
- Section
- M30-M36
Use when the record says
- Mixed connective tissue disease
Indexed under
- Disease, diseased › mixed connective tissue
- Syndrome › connective tissue › overlap NEC
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