What is ICD-10 code J84.2?

J84.2 is the ICD-10-CM diagnosis code for Lymphoid interstitial pneumonia. A lung disease where immune cells accumulate in the tissue between air sacs, causing inflammation and breathing difficulties. It belongs to the ICD-10-CM chapter for diseases of the respiratory system (j00-j99). J84.2 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. J84.2 is part of the FY2026 ICD-10-CM code set published by the CMS National Center for Health Statistics and used on Medicare, Medicaid, and commercial claims in the United States.

Yes. J84.2 is a billable ICD-10-CM code that can be reported on professional and institutional claims as a primary or secondary diagnosis when the provider documentation supports the specific condition described. Billable codes in ICD-10-CM are coded to the highest level of specificity available for the documented diagnosis. J84.2 is current for fiscal year 2026 and remains in the active CMS ICD-10-CM code set published by the National Center for Health Statistics.

Which HCC does J84.2 map to under V28?

J84.2 maps to CMS-HCC V28 HCC 280 (Chronic Obstructive Pulmonary Disease, Interstitial Lung Disorders, and Other Chronic Lung Disorders). The category numbers, labels, and conditions come from the CMS-HCC V28 model file for payment year 2026.

2026 ICD-10-CM J84.2: Lymphoid interstitial

J84.2 maps to CMS-HCC V28 280. A source-labeled RAF reference is available. Documentation must support MEAT. MEAT criteria · RAF Calculator · free HCC coding tools

ICD-10-CM Code View

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Digital ICD-10 code-book layout with official code detail, always-visible risk models, Code Trumping, and Buddy coding guidance.

Code lookupJ84.2Effective periodFY2026 Apr Update (Apr 1-Sep 30)

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

J84.2

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

Lymphoid interstitial pneumonia

A lung disease where immune cells accumulate in the tissue between air sacs, causing inflammation and breathing difficulties.

Buddy Insight

Lymphoid interstitial pneumonia is a rare lymphoproliferative disorder of the lung characterized by diffuse lymphocytic infiltration of the pulmonary interstitium.

CMS-HCC V28

Mapped

HCC 280

Chronic Obstructive Pulmonary...

Code-level coefficient reference

CMS-HCC V24

Historical

Not used for standard CY2026 Medicare Advantage payment. Select a historical period to review V24.

Not used for CY2026 payment

ACA/HHS

Mapped

HCC 162

HHS-HCC 162 adult, RAF varies...

Code-level coefficient reference

ESRD/PACE

Mapped

HCC 112

Fibrosis of Lung and Other Ch...

Code-level coefficient reference

RXHCC

Mapped

HCC 227

Pulmonary Fibrosis, Except Id...

Code-level coefficient reference

Code Book Path

Official

J84Other interstitial pulmonary diseases

J84.2Lymphoid interstitial pneumonia

Inclusion Terms

Official

Lymphoid interstitial pneumonitis

Excludes 2

Official

lung diseases due to external agents (J60-J70)

Related Child Codes

Official

J84.0Alveolar and parieto-alveolar conditions

J84.1Other interstitial pulmonary diseases with fibrosis

J84.8Other specified interstitial pulmonary diseases

J84.9Interstitial pulmonary disease, unspecified

Includes

Official

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

Excludes 1

Official

drug-induced interstitial lung disorders (J70.2-J70.4)
interstitial emphysema (J98.2)

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for J84.2 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for J84.2 in this effective period.

Code Also

Official

, if applicable, associated condition

Buddy Documentation Tip

HCC Buddy guidance

Lung biopsy confirming lymphoid interstitial pneumonia pattern with diffuse lymphocytic infiltration

High-resolution computed tomography findings (ground-glass opacities, thin-walled cysts, centrilobular nodules)

Documentation of associated conditions (Sjogren syndrome, HIV, other autoimmune diseases, immunodeficiency)

Exclusion of lymphoma and other lymphoproliferative malignancies

MEAT Support

HCC Buddy guidance

Lung biopsy confirming lymphoid interstitial pneumonia pattern with diffuse lymphocytic infiltration

High-resolution computed tomography findings (ground-glass opacities, thin-walled cysts, centrilobular nodules)

Documentation of associated conditions (Sjogren syndrome, HIV, other autoimmune diseases, immunodeficiency)

Exclusion of lymphoma and other lymphoproliferative malignancies

Audit Caution

HCC Buddy guidance

Failing to code the associated underlying condition (Sjogren syndrome, HIV) which may contribute additional HCC value

Confusing LIP with pulmonary lymphoma — LIP is benign but requires surveillance for malignant transformation

Using nonspecific interstitial lung disease codes when LIP has been confirmed on biopsy

Not recognizing LIP as a potential AIDS-defining illness in HIV-positive patients

Common Mistakes

HCC Buddy guidance

C85.9 — Non-Hodgkin lymphoma unspecified must be excluded, as LIP can transform to lymphoma

J84.111 — Idiopathic interstitial pneumonia NOS does not capture the specific lymphoid pattern

J84.89 — Other specified interstitial pulmonary diseases is less specific than the dedicated LIP code

D47.Z2 — Follicular dendritic cell sarcoma is a lymphoproliferative disorder but malignant, unlike LIP

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 J84.2 an HCC code?

Yes. J84.2 (Lymphoid interstitial pneumonia) maps to HCC 280, Chronic Obstructive Pulmonary Disease, Interstitial Lung Disorders, and Other Chronic Lung Disorders under the CMS-HCC V28 risk adjustment model, with a source-labeled community non-dual aged reference coefficient of 0.319. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes. It is billable for payment year 2026.

Coder answer: J84.2 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: J84.2
Description: Lymphoid interstitial pneumonia
HCC (V28): HCC 280 — Chronic Obstructive Pulmonary Disease, Interstitial Lung Disorders, and Other Chronic Lung Disorders
RAF reference coefficient: 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

ESRDHCC 112, Fibrosis of Lung and Other Chronic Lung Disorders

Not separately weighted

RxHCCHCC 227, Pulmonary Fibrosis, Except Idiopathic

Not separately weighted

These are source-labeled model coefficients, not member totals. A category may still be removed by hierarchy or model cleanup rules. 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 context, hierarchy and cleanup rules, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains available for historical review.

Work J84.2 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →

MEAT Criteria for J84.2

For J84.2 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 J84.2 during that encounter, not just copy-forwarded from a problem list.

Coder workflow notes

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What This Code Means

J84.2 is the ICD-10-CM diagnosis code for lymphoid interstitial pneumonia. A lung disease where immune cells accumulate in the tissue between air sacs, causing inflammation and breathing difficulties. J84.2 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, J84.2 maps to Chronic Obstructive Pulmonary Disease, Interstitial Lung Disorders, and Other Chronic Lung Disorders (HCC 280) with a source-labeled community, non-dual, aged reference coefficient of 0.319. No V24 mapping is shown for J84.2; use the applicable model and payment year when reviewing the V28 mapping. 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. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes.

Confirm lymphoid infiltration on biopsy or imaging to differentiate from other interstitial pneumonias. Because J84.2 maps to an HCC category, the provider's documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) before the diagnosis is used for risk adjustment. 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, source-labeled coefficient references, and MEAT documentation criteria for J84.2 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•Confirm lymphoid infiltration on biopsy or imaging to differentiate from other interstitial pneumonias
•Document any associated autoimmune conditions that may be present

Clinical Significance

Lymphoid interstitial pneumonia is a rare lymphoproliferative disorder of the lung characterized by diffuse lymphocytic infiltration of the pulmonary interstitium. It is frequently associated with autoimmune conditions (particularly Sjogren syndrome) and immunodeficiency states including HIV. Accurate coding reflects the complex multisystem management these patients require.

Documentation Requirements

✓Lung biopsy confirming lymphoid interstitial pneumonia pattern with diffuse lymphocytic infiltration
✓High-resolution computed tomography findings (ground-glass opacities, thin-walled cysts, centrilobular nodules)
✓Documentation of associated conditions (Sjogren syndrome, HIV, other autoimmune diseases, immunodeficiency)
✓Exclusion of lymphoma and other lymphoproliferative malignancies
✓Treatment plan and monitoring for potential transformation to lymphoma

Commonly Confused Codes

•C85.9: Non-Hodgkin lymphoma unspecified must be excluded, as LIP can transform to lymphoma
•J84.111: Idiopathic interstitial pneumonia NOS does not capture the specific lymphoid pattern
•J84.89: Other specified interstitial pulmonary diseases is less specific than the dedicated LIP code
•D47.Z2: Follicular dendritic cell sarcoma is a lymphoproliferative disorder but malignant, unlike LIP