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J20.8 vs J42

J20.8 (Acute bronchitis due to other specified organisms) compared with J42 (Unspecified chronic bronchitis), from the official CMS tabular data.

Current data releases:ICD-10-CM FY2027 · ICD-10-PCS FY2027 · HCPCS October 2026 · MS-DRG v44 · Medicare Code Editor v44.0 · NCCI PTP Q4 2026 · MUE Q4 2026 · NCD code lists 2026-01 · LCD export September 28, 2026 · All releases and sources

Summary

These codes can be reported together when both conditions are documented, because J20.8 lists J42 under Excludes2, which marks them as distinct conditions.

Official rule
What is different?

The conditions named.J20.8 is “Acute bronchitis due to other specified organisms”; J42 is “Unspecified chronic bronchitis”.

Registry fact

Can these codes be reported together?

Yes, when both are documented.J20.8 lists J42 under Excludes2: “chronic bronchitis NOS (J42)”. Excludes2 marks distinct conditions that may both be reported when both are documented.

Official ruleGuide: Excludes1 vs Excludes2

Is there an Excludes2 relationship?

Yes.J20.8’s tabular entry: “chronic bronchitis NOS (J42)”. The note covers J42.

Official ruleGuide: Excludes1 vs Excludes2

Nothing found in 4 other checks; 1 check does not apply
Is there an Excludes1 relationship?

None.Neither entry carries an Excludes1 note that names the other code. J20.8 carries 2 Excludes1 notes and J42 carries 7 Excludes1 notes covering other codes; the side-by-side table quotes them.

Official rule

Is one more specific?

Not comparable.The codes sit in different categories; specificity is only comparable within one category.

Is one a parent or header code?

No.Both are billable codes, and neither contains the other.

Registry fact

Are there sequencing instructions?

None.Neither entry carries a Code First or Use Additional Code note that names the other.

Official rule

Are there other coding relationships?

None found.No laterality, encounter-phase, Table of Neoplasms, Table of Drugs and Chemicals, or history-versus-active-disease relationship links these codes.

MedCoder-derived

Official rule: a tabular instructional note or a section of the ICD-10-CM Official Guidelines, quoted as published. Registry fact: the codes’ own published attributes (titles, billable status, position in the hierarchy, code set). MedCoder-derived: a reading MedCoder computes from those facts; it is not itself a rule. How to read the labels

Can these codes be reported together?

Informational

Excludes2 relationship

J20.8
Acute bronchitis due to other specified organisms
↔
J42
Unspecified chronic bronchitis

What we found

Yes, when both are documented.J20.8 carries an Excludes2 note covering J42: “chronic bronchitis NOS (J42)”

Excludes2 marks distinct conditions — both may be reported when both are documented.

What to review

Report both only when the documentation supports both conditions; otherwise report the one documented.

Guide: Excludes1 vs Excludes2Check these on a claim

Why it matters

An Excludes2 note means the excluded condition is not part of the code above it, but a patient can have both. Report both when both are documented.

Source / rule

CMS ICD-10-CM tabular instructional notes

Official guidance behind these answers

  • Section I.A.12.b — Excludes2 · applies to: Excludes2

    A type 2 Excludes note represents “Not included here.” An excludes2 note indicates that the condition excluded is not part of the condition represented by the code, but a patient may have both conditions at the same time. When an Excludes2 note appears under a code, it is acceptable to use both the code and the excluded code together, when appropriate.

    ICD-10-CM Official Guidelines FY2027

Quoted from the ICD-10-CM Official Guidelines for Coding and Reporting in effect for the release shown. The tabular notes above are the code-level instruction; these sections are the convention that says how such a note is applied. Source document (CMS PDF) · Release and checksum

Side by side

Similar descriptions do not make codes interchangeable. The documentation and the official instructions decide which code applies.

Official descriptionDiffers
J20.8

Acute bronchitis due to other specified organisms

J42

Unspecified chronic bronchitis

StatusSame for both
Billable
Excludes1Differs
J20.8
  • bronchitis NOS (J40)
  • tracheobronchitis NOS (J40)
J42
  • 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)
Excludes2Differs
J20.8
  • acute bronchitis with bronchiectasis (J47.0)
  • acute bronchitis with chronic obstructive asthma (J44.0)
  • acute bronchitis with chronic obstructive pulmonary disease (J44.0)
  • allergic bronchitis NOS (J45.909)
  • bronchitis due to chemicals, fumes and vapors (J68.0)
  • chronic bronchitis NOS (J42)
  • chronic mucopurulent bronchitis (J41.1)
  • chronic obstructive bronchitis (J44.-)
  • chronic obstructive tracheobronchitis (J44.-)
  • chronic simple bronchitis (J41.0)
  • chronic tracheobronchitis (J42)
  • chronic obstructive pulmonary disease with acute lower respiratory infection (J44.0)
J42
  • cystic fibrosis (E84.-)
Use additional codeDiffers
J20.8

None at this code

J42
  • code to identify:
  • exposure to environmental tobacco smoke (Z77.22)
  • exposure to tobacco smoke in the perinatal period (P96.81)
  • history of tobacco dependence (Z87.891)
  • occupational exposure to environmental tobacco smoke (Z57.31)
  • tobacco dependence (F17.-)
  • tobacco use (Z72.0)
Code alsoDiffers
J20.8

None at this code

J42
  • , if applicable, chronic respiratory conditions due to chemicals, gases, fumes and vapors (J68.4)
CategoryDiffers
J20.8

J20 Acute bronchitis

J42

Is itself a category

ChapterSame for both

J00-J99 — Diseases of the Respiratory System (J00-J99)

IncludesDiffers
J20.8
  • acute and subacute bronchitis (with) bronchospasm
  • acute and subacute bronchitis (with) tracheitis
  • acute and subacute bronchitis (with) tracheobronchitis, acute
  • acute and subacute fibrinous bronchitis
  • acute and subacute membranous bronchitis
  • acute and subacute purulent bronchitis
  • acute and subacute septic bronchitis
J42
  • Chronic bronchitis NOS
  • Chronic tracheitis
  • Chronic tracheobronchitis

No Code first and 7th character note at either code.

Notes are the code’s own tabular entry, quoted as published. A note that names the other code is the one the verdict above rests on. In a row that differs, each code’s own notes are listed under it, and the notes every code shares are listed once beneath them.

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Derived from the official CMS ICD-10-CM tabular data (FY2027). A coding-rule comparison, not billing advice: payer-specific edits and medical-necessity policy are outside its scope. All data sources