ICD-10 code for interstitial pneumonia

The ICD-10-CM code for interstitial pneumonia is J84.9 (Interstitial pulmonary disease, unspecified). The official index lists 19 more specific codes, so check the documentation for details such as type, cause, site or severity before settling on J84.9.

Within J84, choose J84.9 (Interstitial pulmonary disease, unspecified) only when documentation doesn't support a more specific option: alveolar and parieto-alveolar conditions (J84.0), with fibrosis (J84.1), lymphoid interstitial pneumonia (J84.2) and other specified interstitial pulmonary diseases (J84.8).

As a secondary diagnosis it is a CC (complication or comorbidity), which can move an inpatient stay into the "with CC" MS-DRG of its family, unless the principal diagnosis excludes it.

In MS-DRG v44.0, it is part of the grouping logic for DRG 196 (Interstitial Lung Disease with MCC, relative weight 1.8336), DRG 197 (Interstitial Lung Disease with CC, relative weight 0.9492) and DRG 198 (Interstitial Lung Disease without CC/MCC, relative weight 0.7259), in MDC 04 (Diseases and Disorders of the Respiratory System), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.