J84.82 ICD-10-CM Code: Adult pulmonary Langerhans cell histiocytosis
J84.82 maps to CMS-HCC V28 280. A source-labeled RAF reference is available. Confirm the documented diagnosis and applicable coding requirements. MEAT criteria · RAF Calculator · HCC coding software
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FY 2026 Apr update / Diseases of the respiratory system (J00-J99) / Other respiratory diseases principally affecting the interstitium (J80-J84)
J84.82
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceAdult pulmonary Langerhans cell histiocytosis
A rare lung disease in adults where abnormal immune cells accumulate in lung tissue, often related to smoking history.
Buddy Insight
Adult pulmonary Langerhans cell histiocytosis is a rare smoking-related cystic and nodular lung disease caused by clonal proliferation of Langerhans cells in the lungs.
CMS-HCC V28
MappedHCC 280
Coefficient HCC 280: 0.319 (Community Non-Dual Aged (CNA))
CMS-HCC V24
HistoricalHistorical
Not used for CY2026 payment
ACA/HHS
Context neededHCC 162
Coefficient needs member context
ESRD/PACE
Context neededHCC 112
Coefficient needs member context
RXHCC
Context neededHCC 227
Coefficient needs member context
Code Book Path
Inclusion Terms
Official- Adult PLCH
Excludes 2
Official- certain conditions originating in the perinatal period (P04-P96)Inherited from J00-J99, J84
- certain infectious and parasitic diseases (A00-B99)Inherited from J00-J99, J84
- complications of pregnancy, childbirth and the puerperium (O00-O9A)Inherited from J00-J99, J84
- congenital malformations, deformations and chromosomal abnormalities (Q00-Q99)Inherited from J00-J99, J84
- endocrine, nutritional and metabolic diseases (E00-E88)Inherited from J00-J99, J84
- injury, poisoning and certain other consequences of external causes (S00-T88)Inherited from J00-J99, J84
- neoplasms (C00-D49)Inherited from J00-J99, J84
- smoke inhalation (T59.81-)Inherited from J00-J99, J84
- symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)Inherited from J00-J99, J84
- lung diseases due to external agents (J60-J70)Inherited from J00-J99, J84
Related Codes
Includes
OfficialNo Includes notes are included in this display for J84.82. Check the code and parent instructions in the Code Book.
Excludes 1
Official- drug-induced interstitial lung disorders (J70.2-J70.4)Inherited from J84, J84.8
- interstitial emphysema (J98.2)Inherited from J84, J84.8
- exogenous lipoid pneumonia (J69.1)Inherited from J84, J84.8
- unspecified lipoid pneumonia (J69.1)Inherited from J84, J84.8
Code First
OfficialNo Code First sequencing instructions are included in this display for J84.82. Check the code and parent instructions in the Code Book.
Use Additional
Official- code, where applicable, to identify:Inherited from J00-J99
- exposure to environmental tobacco smoke (Z77.22)Inherited from J00-J99
- exposure to tobacco smoke in the perinatal period (P96.81)Inherited from J00-J99
- history of tobacco dependence (Z87.891)Inherited from J00-J99
- occupational exposure to environmental tobacco smoke (Z57.31)Inherited from J00-J99
- tobacco dependence (F17.-)Inherited from J00-J99
- tobacco use (Z72.0)Inherited from J00-J99
Code Also
Official- , if applicable, associated conditionInherited from J84
Buddy Documentation Tip
MEAT Support
Audit Caution
Common Mistakes
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 J84.82 an HCC code?
Yes. J84.82 (Adult pulmonary Langerhans cell histiocytosis) 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: J84.82 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
- J84.82
- Description
- Adult pulmonary Langerhans cell histiocytosis
- 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
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 J84.82 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →
MEAT review for J84.82
For J84.82, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule.
- 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
Coder workflow notes
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What This Code Means
J84.82 is the ICD-10-CM diagnosis code for adult pulmonary langerhans cell histiocytosis. A rare lung disease in adults where abnormal immune cells accumulate in lung tissue, often related to smoking history. J84.82 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, J84.82 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. For CY2026 non-PACE Medicare Advantage, CMS uses 100% of the 2024 CMS-HCC model (V28). PACE uses a separate model blend. 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 diagnosis through biopsy showing Langerhans cell infiltration. For J84.82, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule. 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 J84.82 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Confirm diagnosis through biopsy showing Langerhans cell infiltration
- •Document smoking status, as this is strongly associated with the condition
Clinical Significance
Adult pulmonary Langerhans cell histiocytosis is a rare smoking-related cystic and nodular lung disease caused by clonal proliferation of Langerhans cells in the lungs. This condition is strongly associated with cigarette smoking and requires aggressive smoking cessation, monitoring for disease progression, and potential immunosuppressive therapy. It can progress to respiratory failure and may require transplant evaluation.
Documentation Requirements
- ✓High-resolution computed tomography showing combination of nodules and cysts predominantly in upper and middle lung zones with costophrenic angle sparing
- ✓Bronchoalveolar lavage showing elevated CD1a+ cells (>5%) or lung biopsy confirming Langerhans cell infiltration
- ✓Documented smoking history (strong association with current/recent smoking)
- ✓Evaluation for extrapulmonary Langerhans cell histiocytosis involvement (bone, pituitary, skin)
- ✓Pulmonary function tests documenting the pattern and severity of lung impairment
Commonly Confused Codes
- •J84.81: Lymphangioleiomyomatosis also causes cystic lung disease but in young women with different cyst morphology
- •J43.9: Emphysema unspecified can appear similar with upper lobe cystic changes in smokers
- •C96.6: Unifocal Langerhans cell histiocytosis is a different, more localized form
- •J84.89: Other specified interstitial pulmonary diseases should not be used when PLCH is specifically diagnosed