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ICD-10-CM J84.9: Interstitial pulmonary disease, unspecified

J84.9 is the billable ICD-10-CM code for interstitial pulmonary disease, unspecified, in category J84 (Other interstitial pulmonary diseases) of the Other respiratory diseases principally affecting the interstitium section. As a principal diagnosis it groups to MS-DRG 196 Interstitial Lung Disease with MCC, MS-DRG 197 Interstitial Lung Disease with CC, MS-DRG 198 Interstitial Lung Disease without CC/MCC (MDC 04 MDC 04: Diseases and Disorders of the Respiratory System). It maps to HCC 280 (Chronic Obstructive Pulmonary Disease, Interstitial Lung Disorders, and Other Chronic Lung Disorders) in CMS-HCC V28. As a secondary diagnosis it is a CC, excluded with 90 principal diagnoses. 10 LCD billing and coding articles list it as covered.

Compiled from CMS files by the QuickIntell RCM Editorial Team · Data effective · Method: reference methodology · Report a data correction

Data currency: ICD-10-CM code descriptions: FY2027 (effective October 1, 2026); IPPS Table 5 (MS-DRG weights): v44 FY2027 (final rule + CN3) (effective October 1, 2026); ICD-10-CM to HCC mapping: PY2027 initial ICD-10-CM mappings (dates of service 2026) (payment year 2027); Medicare Coverage Database billing and coding articles: MCD release October 8, 2026 (effective October 4, 2026). Next CMS release: FY2028 code files, effective October 1, 2027 for the ICD-10-CM code descriptions; FY2028 final rule (August 2027), effective October 1, 2027; an April 1 interim grouper update when CMS issues one for the IPPS Table 5 (MS-DRG weights); PY2028 advance notice (February 2027) and the PY2027 midyear final mapping (spring 2027) for the ICD-10-CM to HCC mapping; weekly, every Thursday for the Medicare Coverage Database billing and coding articles.

Code
J84.9
billable FY2027 ICD-10-CM code
Category
J84 Other interstitial pulmonary diseases
Chapter
10: Diseases of the respiratory system (J00-J99)
CC/MCC (MS-DRG v44)
CC
CMS-HCC V28
HCC 280
POA reporting
Required

Tabular list notes for J84.9

Inclusion terms
  • Interstitial pneumonia NOS

Inherited from J84 (Other interstitial pulmonary diseases)

Excludes1 (never coded together)
  • drug-induced interstitial lung disorders (J70.2-J70.4)
  • interstitial emphysema (J98.2)
Excludes2 (not part of this condition, may be coded together)
  • lung diseases due to external agents (J60-J70)
Code also
  • , if applicable, associated condition

MS-DRG grouping when J84.9 is the principal diagnosis

MS-DRG v44 groups for J84.9 as principal diagnosis
MDCMS-DRGs
04 MDC 04: Diseases and Disorders of the Respiratory System196197198

The final group also depends on procedures, secondary diagnoses and discharge status; the MS-DRG lookup for J84.9 shows the full grouping logic.

CC/MCC status and inpatient edits

As a secondary diagnosis, J84.9 is a CC under MS-DRG v44, unless the principal diagnosis is one of the 90 codes in its exclusion list. Check J84.9 against a principal diagnosis.

  • Present on admission: a POA indicator is required on inpatient claims.

CMS-HCC V28 risk adjustment

In the PY2027 mapping, J84.9 maps to HCC 280 (Chronic Obstructive Pulmonary Disease, Interstitial Lung Disorders, and Other Chronic Lung Disorders). The HCC lookup shows the RAF weight and the hierarchy.

LCD billing and coding articles that list J84.9

10 current Medicare billing and coding articles list J84.9 among the diagnoses that support medical necessity for the services they cover.

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Frequently asked questions

What does ICD-10-CM J84.9 mean?

J84.9 means interstitial pulmonary disease, unspecified. The tabular list also files these terms under it: Interstitial pneumonia NOS. It is one of 24 billable codes under J84, other interstitial pulmonary diseases.

What can't be coded with J84.9?

Excludes1 at J84: drug-induced interstitial lung disorders (J70.2-J70.4); interstitial emphysema (J98.2). These are never reported together with J84.9.

Which MS-DRG does J84.9 group to?

As the principal diagnosis, J84.9 groups to MS-DRG 196 Interstitial Lung Disease with MCC, MS-DRG 197 Interstitial Lung Disease with CC, MS-DRG 198 Interstitial Lung Disease without CC/MCC (MDC 04 MDC 04: Diseases and Disorders of the Respiratory System) under MS-DRG v44, before procedures and secondary diagnoses are applied.

Does J84.9 map to an HCC?

Yes: HCC 280, Chronic Obstructive Pulmonary Disease, Interstitial Lung Disorders, and Other Chronic Lung Disorders, in the PY2027 CMS-HCC V28 mapping.

Is J84.9 a CC or MCC?

J84.9 is a CC under MS-DRG v44; 90 principal diagnoses exclude it.

Sources

Every figure on this page is taken from the CMS publications below, as released by the Centers for Medicare & Medicaid Services. Projection built 2026-10-10. Verify against the primary file before billing or contracting decisions. The reference methodology explains how each figure is computed from these files.

Disclaimer

The descriptor and notes are reproduced from the FY2027 ICD-10-CM files; MS-DRG, CC/MCC and HCC facts come from the CMS FY2027 and PY2027 tables. Code from the medical record and the ICD-10-CM Official Guidelines. Not legal, clinical or billing advice.

Found a figure that does not match the CMS file? Report a data correction with the CMS file and the value you expected; the request reaches the editorial team through the contact form.