M31.5 vs M35.3
M31.5 and M35.3 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 M35.3
polymyalgia rheumatica with giant cell arteritis (M31.5)
M31.5
Giant cell arteritis with polymyalgia rheumatica
Billable
- Chapter 13
- Diseases of the musculoskeletal system and connective tissue
- Section
- M30-M36
Indexed under
- Polymyalgia › arteritica, giant cell
- Arteritis › giant cell NEC › with polymyalgia rheumatica
- Polymyalgia › rheumatica › with giant cell arteritis
M35.3
Polymyalgia rheumatica
Billable
- Chapter 13
- Diseases of the musculoskeletal system and connective tissue
- Section
- M30-M36
Indexed under
- Forestier's disease (rhizomelic pseudopolyarthritis)
- Polymyalgia
- Pseudopolyarthritis, rhizomelic
- Disease, diseased › Forestier's
- Polymyalgia › rheumatica
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