J67.4
BillableMaltworker's lung
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is J67.4 an HCC code?
Yes. J67.4 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).
HCC Category Mapping
RAF weights shown are the community, non-dual, aged base weights from the CMS risk adjustment model file. 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.
MEAT Criteria for J67.4
For J67.4to 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 J67.4 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
J67.4 is the ICD-10-CM diagnosis code for maltworker's lung. An allergic lung disease that occurs in workers exposed to moldy barley or other grains during the malting process used in beer and whiskey production. J67.4 sits in the ICD-10-CM chapter for diseases of the respiratory system (j00-j99), within the section covering lung diseases due to external agents (j60-j70).
Under the CMS-HCC V28 risk adjustment model, J67.4 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, J67.4 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.
Document exposure to moldy grain or malt dust in occupational history. Because J67.4 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 J67.4 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Document exposure to moldy grain or malt dust in occupational history
- •Specify if acute, subacute, or chronic presentation when available
Clinical Significance
Maltworker's lung is a form of hypersensitivity pneumonitis caused by inhalation of mold spores (Aspergillus clavatus or fumigatus) during the malting process used in beer and whiskey production. It carries risk adjustment significance as a chronic occupational lung disease that can progress to fibrosis with continued exposure.
Documentation Requirements
- ✓Documented occupational exposure to moldy grain or malt dust in brewing, distilling, or malting operations
- ✓Identification of the specific mold organism if available
- ✓Classification as acute, subacute, or chronic
- ✓Chest imaging findings and pulmonary function test results
- ✓Serum precipitin testing for Aspergillus species if performed
- ✓Treatment plan and work modification recommendations
Commonly Confused Codes
- •J67.0 (Farmer's lung) — general moldy hay/grain vs. specific malting process grain
- •J67.8 (Hypersensitivity pneumonitis due to other organic dusts) — use J67.4 when malt dust is identified
- •B44.x (Aspergillosis codes) — aspergillosis is an infection, not hypersensitivity pneumonitis
- •J67.5 (Mushroom-worker's lung) — different fungal/mold exposure source