J70.4 vs J84.9
J70.4 and J84.9 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 J70.4
interstitial pneumonia NOS (J84.9)
J70.4
Drug-induced interstitial lung disorders, unspecified
BillableUnspecified
- Chapter 10
- Diseases of the respiratory system
- Section
- J60-J70
Indexed under
- Disorder › lung, interstitial, drug-induced (of)
- Pneumonitis › chemotherapy (acute) (primary)
J84.9
Interstitial pulmonary disease, unspecified
BillableUnspecified
- Chapter 10
- Diseases of the respiratory system
- Section
- J80-J84
Use when the record says
- Interstitial pneumonia NOS
Indexed under
- Pneumonia › interstitial (acute) (double) (migratory) (purulent) (septic) (unresolved)
- Disease, diseased › lung › interstitial
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