J18Pneumonia, unspecified organism

J18 is the ICD-10-CM diagnosis code for pneumonia, unspecified organism. It belongs to block J09-J18 (influenza and pneumonia) and chapter 10 (diseases of the respiratory system). It is a header code, so it can't be reported by itself; one of its 5 subcodes must be used instead.

To report this condition, pick the subcode that matches the documentation: J18.0 (organism), J18.1 (organism), J18.2 (organism), J18.8 (organism) and J18.9 (organism).

Don't report J18 together with the conditions in its Excludes1 note: congenital pneumonia (P23.0), drug-induced interstitial lung disorder (J70.2-J70.4), interstitial pneumonia NOS (J84.9), neonatal aspiration pneumonia (P24.-) and 2 more.

The conditions in its Excludes2 note aren't part of J18, but may be coded alongside it if the patient has both: abscess of lung with pneumonia (J85.1), aspiration pneumonia due to anesthesia during labor and delivery (O74.0), aspiration pneumonia due to anesthesia during pregnancy (O29), aspiration pneumonia due to anesthesia during puerperium (O89.0) and 4 more.

Code first: , if applicable, associated influenza (J09.X1, J10.0-, J11.0-).

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.