Excludes1 pair
J18- vs J84.9
J18 and J84.9 are not coded together. ICD-10-CM declares them mutually exclusive with an Excludes1 note — the two conditions are not expected to occur together, so exactly one of them is normally correct for a given encounter. The Official Guidelines carve out one exception: if the two conditions are clearly unrelated to each other, both may be reported.
The official note, declared on J18
interstitial pneumonia NOS (J84.9)
J18
Pneumonia, unspecified organism
Not billable
- Chapter 10
- Diseases of the respiratory system
- Section
- J09-J18
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
- 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