J90 vs R09.1

J90 and R09.1 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 J90

pleurisy NOS (R09.1)

J90

Pleural effusion, not elsewhere classified

BillableUnspecified

Chapter 10: Diseases of the respiratory system
Section: J90-J94

Use when the record says

Encysted pleurisy
Pleural effusion NOS
Pleurisy with effusion (exudative) (serous)

Indexed under

Effusion › pleura, pleurisy, pleuritic, pleuropericardial
Pleurisy › pneumococcal (acute) (adhesive) (chronic) (costal) (diaphragmatic) (double) (dry) (fibrinous) (fibrous) (interlobar) (latent) (plastic) (primary) (residual) (sicca) (sterile) (subacute) (unresolved)
Pleurisy › streptococcal (acute) (adhesive) (chronic) (costal) (diaphragmatic) (double) (dry) (fibrinous) (fibrous) (interlobar) (latent) (plastic) (primary) (residual) (sicca) (sterile) (subacute) (unresolved)
Pleurisy › with › effusion (acute) (adhesive) (chronic) (costal) (diaphragmatic) (double) (dry) (fibrinous) (fibrous) (interlobar) (latent) (plastic) (primary) (residual) (sicca) (sterile) (subacute) (unresolved)

R09.1

Pleurisy

Billable

Chapter 18: Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified
Section: R00-R09

Indexed under

Pleurisy (acute) (adhesive) (chronic) (costal) (diaphragmatic) (double) (dry) (fibrinous) (fibrous) (interlobar) (latent) (plastic) (primary) (residual) (sicca) (sterile) (subacute) (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