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J84.111 ICD-10-CM Code: Idiopathic interstitial pneumonia, not otherwise specified

J84.111 maps to CMS-HCC V28 280 (RAF 0.319). Documentation must support MEAT. MEAT criteria · RAF calculator · HCC Buddy coding tools

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FY 2026 Apr update / Diseases of the respiratory system (J00-J99) / Other respiratory diseases principally affecting the interstitium (J80-J84)

J84.111

Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidance

Idiopathic interstitial pneumonia, not otherwise specified

Inflammation of the lung tissue with unknown cause that doesn't fit into other specific interstitial pneumonia categories.

Buddy the Bee presenting code insight

Buddy Insight

Idiopathic interstitial pneumonia not otherwise specified represents a significant diagnostic category in risk adjustment because it indicates chronic, progressive lung disease requiring ongoing specialist management.

CMS-HCC V28

HCC 280

RAF 0.319

CMS-HCC V24

HCC 112

RAF 0.219

ACA/HHS

HCC 162

Varies by metal level

ESRD/PACE

HCC 112

RAF 0.058

RXHCC

HCC 227

RAF 0.398

Code Book Path

Official
J84.1Other interstitial pulmonary diseases with fibrosis
J84.11Idiopathic interstitial pneumonia
J84.111Idiopathic interstitial pneumonia, not otherwise specified

Inclusion Terms

Official

ICD-10-CM does not list inclusion terms for J84.111 in this effective period.

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for J84.111 in this effective period.

Related Child Codes

Official
J84.112Idiopathic pulmonary fibrosis
J84.113Idiopathic non-specific interstitial pneumonitis
J84.114Acute interstitial pneumonitis
J84.115Respiratory bronchiolitis interstitial lung disease
J84.116Cryptogenic organizing pneumonia

Includes

Official

ICD-10-CM does not list Includes notes for J84.111 in this effective period.

Excludes 1

Official
  • lymphoid interstitial pneumonia (J84.2)
  • pneumocystis pneumonia (B59)

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for J84.111 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for J84.111 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for J84.111 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance
Pulmonologist or treating physician documentation confirming the idiopathic interstitial pneumonia diagnosis
High-resolution computed tomography findings or lung biopsy results supporting the diagnosis
Documentation that other causes of interstitial pneumonia have been excluded (infections, drugs, connective tissue disease, environmental exposures)
Current disease status, severity, and functional impact (e.g., oxygen requirements, pulmonary function test results)

MEAT Support

HCC Buddy guidance
Pulmonologist or treating physician documentation confirming the idiopathic interstitial pneumonia diagnosis
High-resolution computed tomography findings or lung biopsy results supporting the diagnosis
Documentation that other causes of interstitial pneumonia have been excluded (infections, drugs, connective tissue disease, environmental exposures)
Current disease status, severity, and functional impact (e.g., oxygen requirements, pulmonary function test results)

Audit Caution

HCC Buddy guidance
Assigning this code when a more specific subtype (IPF, NSIP, COP, DIP, RB-ILD) has been identified — always use the most specific code available
Failing to verify that the interstitial pneumonia is truly idiopathic and not secondary to a known cause like rheumatoid arthritis or drug toxicity
Confusing this with infectious pneumonia codes (J12-J18) which represent acute infections, not chronic interstitial disease
Using this code for acute presentations without confirming the chronic interstitial component

Common Mistakes

HCC Buddy guidance
J84.112 — Idiopathic pulmonary fibrosis is a specific subtype with UIP pattern; J84.111 is used when the specific IIP subtype cannot be determined
J84.113 — Idiopathic non-specific interstitial pneumonitis has a distinct NSIP pattern on imaging/biopsy unlike NOS
J84.9 — Interstitial pulmonary disease unspecified is less specific and should not be used when idiopathic interstitial pneumonia is documented
J84.89 — Other specified interstitial pulmonary diseases covers known-cause interstitial diseases, not idiopathic ones

Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →

Is J84.111 an HCC code?

Yes. J84.111 (Idiopathic interstitial pneumonia, not otherwise specified) maps to Chronic Obstructive Pulmonary Disease, Interstitial Lung Disorders, and Other Chronic Lung Disorders under the CMS-HCC V28 risk adjustment model (and Fibrosis of Lung and Other Chronic Lung Disorders under V24), with a community non-dual aged RAF of 0.319. It is billable for payment year 2026.

Coder answer: J84.111 is billable and maps to V28 HCC 280, Chronic Obstructive Pulmonary Disease, Interstitial Lung Disorders, and Other Chronic Lung Disorders. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.

Code
J84.111
Description
Idiopathic interstitial pneumonia, not otherwise specified
HCC (V28)
HCC 280 — Chronic Obstructive Pulmonary Disease, Interstitial Lung Disorders, and Other Chronic Lung Disorders
RAF
0.319
Billable
Yes
Payment year
2026

HCC Category Mapping

V28HCC 280, Chronic Obstructive Pulmonary Disease, Interstitial Lung Disorders, and Other Chronic Lung Disorders
0.319
V24HCC 112, Fibrosis of Lung and Other Chronic Lung Disorders
0.219
ESRDHCC 112, Fibrosis of Lung and Other Chronic Lung Disorders
0.058
RxHCCHCC 227, Sarcoidosis, Pulmonary Alveolar Disorders
0.398

Each model's RAF is its CMS base weight for that model's standard population, so weights are not directly comparable across models: CMS-HCC V28 and V24 use Community, Non-Dual, Aged; ESRD uses the dialysis continuing-enrollee model; RxHCC is the Part D continuing-enrollee, non-low-income, aged weight (a larger scale than CMS-HCC). ACA/HHS has no single weight — it varies by metal level. Actual per-patient RAF contribution depends on member segment, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains in use during the transition and for historical data.

Work J84.111 in the Code Book — tabular path, V28 RAF, and MEAT checklist →

MEAT Criteria for J84.111

For J84.111 to count as a valid HCC diagnosis in a given encounter, the provider's documentation must show MEAT: Monitor, Evaluate, Assess, or Treat. A diagnosis from a prior year does not carry forward automatically, it has to be re-documented and supported each calendar year.

  • MMonitor: signs, symptoms, disease progression, or lab trending documented in the note
  • EEvaluate: test results, medication response, or physical findings reviewed by the provider
  • AAssess: explicit mention in the assessment or plan with acknowledgment of status
  • TTreat: medication, referral, procedure, therapy, or counseling tied to the diagnosis

Only one of M/E/A/T is required to support the code, but the documentation must be specific enough to show that the provider actually addressed J84.111 during that encounter, not just copy-forwarded from a problem list.

Coder workflow notes

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What This Code Means

J84.111 is the ICD-10-CM diagnosis code for idiopathic interstitial pneumonia, not otherwise specified. Inflammation of the lung tissue with unknown cause that doesn't fit into other specific interstitial pneumonia categories. J84.111 sits in the ICD-10-CM chapter for diseases of the respiratory system (j00-j99), within the section covering other respiratory diseases principally affecting the interstitium (j80-j84).

Under the CMS-HCC V28 risk adjustment model, J84.111 maps to Chronic Obstructive Pulmonary Disease, Interstitial Lung Disorders, and Other Chronic Lung Disorders (HCC 280) with a community, non-dual, aged base RAF weight of 0.319. Under the older CMS-HCC V24 model, J84.111 maps to Fibrosis of Lung and Other Chronic Lung Disorders (HCC 112) with a community, non-dual, aged base RAF weight of 0.219. V28 is the CMS-HCC risk adjustment model that reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition.

This is a diagnosis of exclusion; ensure other specific interstitial pneumonias have been ruled out. Because J84.111 maps to a payment HCC, the provider's documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's Medicare Advantage risk adjustment score. When documentation is ambiguous, coders should issue a provider query rather than assume the highest-specificity variant.

HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for J84.111 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

  • •This is a diagnosis of exclusion; ensure other specific interstitial pneumonias have been ruled out
  • •Document clinical, radiological, and pathological findings supporting this diagnosis

Clinical Significance

Idiopathic interstitial pneumonia not otherwise specified represents a significant diagnostic category in risk adjustment because it indicates chronic, progressive lung disease requiring ongoing specialist management. This diagnosis reflects substantial resource utilization including pulmonary function monitoring, imaging surveillance, and potential immunosuppressive therapy. Accurate capture ensures appropriate risk-adjusted payment for the complexity of care these patients require.

Documentation Requirements

  • ✓Pulmonologist or treating physician documentation confirming the idiopathic interstitial pneumonia diagnosis
  • ✓High-resolution computed tomography findings or lung biopsy results supporting the diagnosis
  • ✓Documentation that other causes of interstitial pneumonia have been excluded (infections, drugs, connective tissue disease, environmental exposures)
  • ✓Current disease status, severity, and functional impact (e.g., oxygen requirements, pulmonary function test results)
  • ✓Treatment plan including medications and follow-up schedule

Commonly Confused Codes

  • •J84.112: Idiopathic pulmonary fibrosis is a specific subtype with UIP pattern; J84.111 is used when the specific IIP subtype cannot be determined
  • •J84.113: Idiopathic non-specific interstitial pneumonitis has a distinct NSIP pattern on imaging/biopsy unlike NOS
  • •J84.9: Interstitial pulmonary disease unspecified is less specific and should not be used when idiopathic interstitial pneumonia is documented
  • •J84.89: Other specified interstitial pulmonary diseases covers known-cause interstitial diseases, not idiopathic ones

Child Codes

J84.111Idiopathic interstitial pneumonia, not otherwise specified
HCC 280
J84.112Idiopathic pulmonary fibrosis
HCC 278
J84.113Idiopathic non-specific interstitial pneumonitis
HCC 280
J84.114Acute interstitial pneumonitis
HCC 280
J84.115Respiratory bronchiolitis interstitial lung disease
HCC 280
J84.116Cryptogenic organizing pneumonia
HCC 280
J84.117Desquamative interstitial pneumonia
HCC 280

Code Hierarchy

└J84Other interstitial pulmonary diseases└J84.1Other interstitial pulmonary diseases with fibrosis└J84.11Idiopathic interstitial pneumonia└J84.111Idiopathic interstitial pneumonia, not otherwise specified
└J84.111Idiopathic interstitial pneumonia, not otherwise specified

Because J84.111 maps to a payment HCC, the documentation must also satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's risk adjustment score.

J84.111 maps to CMS-HCC V28 category 280, Chronic Obstructive Pulmonary Disease, Interstitial Lung Disorders, and Other Chronic Lung Disorders. See the ICD-10 to HCC mapping hub for how the V28 crosswalk works. Because J84.111 carries a payment HCC, you can see what it adds to a RAF score and check the documentation the chart needs before it is submitted.

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Open J84.111 in the Code Book for the full Index-to-Tabular path, MEAT checklist, and V28 HCC mapping, or in the Encoder to code from a keyword search. Pro includes 7 days to try everything, no card required.

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