M30 vs M31.7
M30 and M31.7 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 M30
microscopic polyarteritis (M31.7)
M30
Polyarteritis nodosa and related conditions
Not billable
- Chapter 13
- Diseases of the musculoskeletal system and connective tissue
- Section
- M30-M36
M31.7
Microscopic polyangiitis
Billable
- Chapter 13
- Diseases of the musculoskeletal system and connective tissue
- Section
- M30-M36
Use when the record says
- Microscopic polyarteritis
Indexed under
- Microscopic polyangiitis (polyarteritis)
- Polyangiitis › microscopic
- Polyarteritis › microscopic
- Disorder › glomerular › microscopic polyangiitis (of)
- Glomerulonephritis › in › microscopic polyangiitis
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