J42 ICD-10-CM Code: Unspecified chronic bronchitis
J42 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 Buddy coding tools
HCC Buddy Code Card
Digital ICD-10 code-book layout with official code detail, always-visible risk models, Code Trumping, and Buddy coding guidance.
FY 2026 Apr update / Diseases of the respiratory system (J00-J99) / Chronic lower respiratory diseases (J40-J4A)
J42
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceUnspecified chronic bronchitis
A long-term inflammation of the airways without specification of the type of mucus production or other distinguishing characteristics.
Buddy Insight
Unspecified chronic bronchitis is used when the provider documents chronic bronchitis without specifying whether the sputum is mucoid, purulent, or mixed.
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 160, HCC 161_1
Coefficient needs member context
ESRD/PACE
Context neededHCC 111, HCC 112
Coefficient needs member context
RXHCC
MappedHCC 229
Code-level coefficient reference
Code Book Path
Inclusion Terms
Official- Chronic bronchitis NOS
- Chronic tracheitis
- Chronic tracheobronchitis
Excludes 2
Official- certain conditions originating in the perinatal period (P04-P96)Inherited from J00-J99, J40-J4A
- certain infectious and parasitic diseases (A00-B99)Inherited from J00-J99, J40-J4A
- complications of pregnancy, childbirth and the puerperium (O00-O9A)Inherited from J00-J99, J40-J4A
- congenital malformations, deformations and chromosomal abnormalities (Q00-Q99)Inherited from J00-J99, J40-J4A
- endocrine, nutritional and metabolic diseases (E00-E88)Inherited from J00-J99, J40-J4A
- injury, poisoning and certain other consequences of external causes (S00-T88)Inherited from J00-J99, J40-J4A
- neoplasms (C00-D49)Inherited from J00-J99, J40-J4A
- smoke inhalation (T59.81-)Inherited from J00-J99, J40-J4A
- symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)Inherited from J00-J99, J40-J4A
- cystic fibrosis (E84.-)Inherited from J00-J99, J40-J4A
Related Codes
No related codes are included in this display for J42. Check the Code Book for the complete code path.
Includes
OfficialNo Includes notes are included in this display for J42. Check the code and parent instructions in the Code Book.
Excludes 1
Official- bronchiolitis obliterans and bronchiolitis obliterans syndrome (J44.81)
- chronic asthmatic bronchitis (J44.-)
- chronic bronchitis with airways obstruction (J44.-)
- chronic emphysematous bronchitis (J44.-)
- chronic obstructive pulmonary disease NOS (J44.9)
- simple and mucopurulent chronic bronchitis (J41.-)
- bronchitis due to chemicals, gases, fumes and vapors (J68.0)Inherited from J40-J4A
Code First
OfficialNo Code First sequencing instructions are included in this display for J42. Check the code and parent instructions in the Code Book.
Use Additional
Official- code to identify:
- 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, where applicable, to identify:Inherited from J00-J99
Code Also
OfficialNo Code Also instructions are included in this display for J42. Check the code and parent instructions in the Code Book.
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 J42 an HCC code?
Yes. J42 (Unspecified chronic bronchitis) 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: J42 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
- J42
- Description
- Unspecified chronic bronchitis
- 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 J42 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →
MEAT review for J42
For J42, 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
Get the V28 mapping + MEAT cheat sheet
One printable reference: check representative V28 mappings and the documentation reminders your note needs. Free, no card.
Free PDF. No card. Unsubscribe anytime.
What This Code Means
J42 is the ICD-10-CM diagnosis code for unspecified chronic bronchitis. A long-term inflammation of the airways without specification of the type of mucus production or other distinguishing characteristics. J42 sits in the ICD-10-CM chapter for diseases of the respiratory system (j00-j99), within the section covering chronic lower respiratory diseases (j40-j4a).
Under the CMS-HCC V28 risk adjustment model, J42 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.
This is a non-specific chronic bronchitis code; query the provider for more detail about sputum characteristics to use J41.0, J41.1, or J41.8. For J42, 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 J42 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
Clinical Significance
Unspecified chronic bronchitis is used when the provider documents chronic bronchitis without specifying whether the sputum is mucoid, purulent, or mixed. While it carries the same HCC mapping as the specified subtypes, coders should query for specificity when possible to improve documentation quality.
Documentation Requirements
- ✓Provider documentation explicitly stating 'chronic bronchitis'
- ✓Duration criteria met: cough with sputum production for at least 3 months in 2 consecutive years
- ✓Current symptom status and any exacerbations
- ✓Treatment plan for chronic bronchitis management
- ✓Exclusion of other causes of chronic cough
Excludes 1, Do NOT code together
Use Additional Code
Commonly Confused Codes
- •J41.0: Simple chronic bronchitis: preferred when mucoid sputum is specified
- •J41.1: Mucopurulent chronic bronchitis: preferred when purulent sputum is specified
- •J40: Bronchitis, not specified as acute or chronic: does NOT map to an HCC; must specify chronicity
- •J44.9: COPD, unspecified: use when COPD with airflow obstruction is documented
- •J20.9: Acute bronchitis, unspecified: completely different condition, acute not chronic