J18 vs P23.0
J18 and P23.0 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 J18
congenital pneumonia (P23.0)
J18
Pneumonia, unspecified organism
Not billable
- Chapter 10
- Diseases of the respiratory system
- Section
- J09-J18
P23.0
Congenital pneumonia due to viral agent
Billable
- Chapter 16
- Certain conditions originating in the perinatal period
- Section
- P19-P29
Indexed under
- Pneumonia › viral, virus › congenital (acute) (double) (migratory) (purulent) (septic) (unresolved)
- Pneumonia › congenital › due to › viral agent (acute) (double) (migratory) (purulent) (septic) (unresolved)
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