B39.2 vs J99
B39.2 and J99 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.
Pulmonary histoplasmosis capsulati, unspecified
- Chapter 1
- Certain infectious and parasitic diseases
- Section
- B35-B49
- Histoplasmosis › with pneumonia NEC
- Histoplasmosis › lung NEC
- Histoplasmosis › capsulati › pulmonary
- Pneumonia › in › histoplasmosis (acute) (double) (migratory) (purulent) (septic) (unresolved)
Respiratory disorders in diseases classified elsewhere
- Chapter 10
- Diseases of the respiratory system
- Section
- J96-J99
- Bronchomycosis NOS
- Pneumomycosis
- Amyloidosis › with lung involvement (generalized) (primary)
- Amyloidosis › pulmonary (generalized) (primary)
- Amyloidosis › subglottic (generalized) (primary)
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