M31.0 vs N08
M31.0 and N08 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 N08
antiglomerular basement membrane disease (M31.0)
M31.0
Hypersensitivity angiitis
Billable
- Chapter 13
- Diseases of the musculoskeletal system and connective tissue
- Section
- M30-M36
Use when the record says
- Goodpasture's syndrome
Indexed under
- Goodpasture's syndrome
- Angiitis › hypersensitivity
- Arteritis › allergic
- Disease, diseased › antiglomerular basement membraneantibody
- Vasculitis › leukocytoclastic
N08
Glomerular disorders in diseases classified elsewhere
Billable
- Chapter 14
- Diseases of the genitourinary system
- Section
- N00-N08
Use when the record says
- Glomerulonephritis
- Nephritis
- Nephropathy
Indexed under
- Nephritis, nephritic › amyloid (albuminuric) (azotemic) (congenital) (disseminated) (epithelial) (familial) (focal) (granulomatous) (hemorrhagic) (infantile) (nonsuppurative, excretory) (uremic)
- Nephropathy › sickle-cell
- Disorder › glomerular › amyloidosis (of)
- Disorder › glomerular › cryoglobulinemia (of)
- Disorder › glomerular › disseminated intravascular coagulation (of)
These two codes sit in different chapters of the Tabular List, which is usually the clearest signal that they describe different underlying processes rather than different degrees of the same one.
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