Excludes1 pair

E84.0 vs J99

E84.0 and J99 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 J99
cystic fibrosis with pulmonary manifestations (E84.0)
E84.0

Cystic fibrosis with pulmonary manifestations

Billable
Chapter 4
Endocrine, nutritional and metabolic diseases
Section
E70-E88
Indexed under
  • Fibrosis, fibrotic › cystic › with › pulmonary manifestations
J99

Respiratory disorders in diseases classified elsewhere

Billable
Chapter 10
Diseases of the respiratory system
Section
J96-J99
Indexed under
  • Bronchomycosis NOS
  • Pneumomycosis
  • Amyloidosis › with lung involvement
  • Amyloidosis › pulmonary
  • Amyloidosis › subglottic

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