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J42 ICD-10-CM Code: Unspecified chronic bronchitis

Billing Status: YES. This is a valid, specific, and billable ICD-10-CM reference.

Coding at a Glance

Tabular directives
3 inclusion terms · 7 Excludes1 · 1 Excludes2 · 7 use-additional codes · 1 code-also instruction
Risk adjustment
CMS-HCC V28: 1 category · CMS-HCC V22 category 111 · RxHCC V08 category 229

Inpatient Payment Groups (MS-DRG)

Potential MS-DRG participation — not a DRG assignment.

MS-DRGs this diagnosis helps define, as principal or secondary, per the CMS ICD-10-CM/PCS MS-DRG Definitions Manual v43, Appendix B.

  • MS-DRG 190 — CHRONIC OBSTRUCTIVE PULMONARY DISEASE WITH MCC (MDC 04)
  • MS-DRG 191 — CHRONIC OBSTRUCTIVE PULMONARY DISEASE WITH CC (MDC 04)
  • MS-DRG 192 — CHRONIC OBSTRUCTIVE PULMONARY DISEASE WITHOUT CC/MCC (MDC 04)

A diagnosis appearing in a group's logic does not by itself determine the DRG assigned to a stay; the grouper uses the full claim.

Risk Adjustment (CMS-HCC)

Payment categories this diagnosis maps to under CMS-HCC V28, payment year 2026.

  • HCC 280 — Chronic Obstructive Pulmonary Disease, Interstitial Lung Disorders, and Other Chronic Lung Disorders

Other models: CMS-HCC V22 HCC 111 · RxHCC V08 HCC 229

Risk scores depend on the enrollee's full accepted diagnosis set and segment; a category mapping alone does not determine payment.

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for J42 in the official ICD-10-CM tabular list, quoted as published.

Source: CMS/CDC — ICD-10-CM Tabular ListRelease: FY2026Effective: October 1, 2025

Notes without a marker are published on J42 itself; “inherited from” names the category or block whose note applies here.

This page already reflects the FY2027 tabular note taking effect October 1, 2026.

Inclusion Terms

Alternative terms the tabular list files under this code.

  • Chronic bronchitis NOS
  • Chronic tracheitis
  • Chronic tracheobronchitis

Excludes1 — Not Coded Here

Conditions generally not reported together with this code (Excludes1) -- an error unless the two conditions are documented as unrelated to each other (ICD-10-CM Official Guidelines, Section I.A.12.a).

Excludes2 — Not Included Here

Conditions not covered by this code, but which may be reported alongside it when both are present.

Source: inherited from J40-J4A

Code Also

Additional codes that may be required to fully describe the encounter.

  • Code also, if applicable, chronic respiratory conditions due to chemicals, gases, fumes and vapors (J68.4)

Use Additional Code

Supplementary codes the tabular list directs you to add.

  • Use additional 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)

Coder workflow for J42

MedCoder structured workflow — derived from this code’s own official record

Before you code J42

  1. Unspecified does not mean incorrect. When the record gives no greater specificity, J42 may be the appropriate code. Check the record for detail that supports a more specific sibling — in this subcategory the siblings differ by acute versus chronic. An unspecified code is for records that do not provide the detail a more specific code needs; a query, not an assumption, is the route to specificity (Guidelines I.A.9.b, I.B.18).

    See the relationships section · Guide: Other vs unspecified (NEC vs NOS) →

  2. Check the Excludes1 note: if the documentation supports a condition named there, do not simply proceed with J42. Excludes1 conditions are not reported together with this code unless the record shows they are unrelated (Guidelines I.A.12.a).

    See the official tabular notes

Choose the right path

  1. Does the record document the detail a more specific sibling code needs?
    Yes → Review the specific siblings in this subcategory.
    No → Continue — J42 is appropriate when the documentation goes no further.
  2. Does the documentation support a condition named in J42’s Excludes1 note?
    Yes → Do not simply proceed: review the excluded code. Both are reported only when the record shows the two conditions are unrelated.
    No → Continue.

    ReviewJ44.81, J44, J44.9, J41, J68.0

Consider J42. Then work the Use Additional Code note and review the Code Also note, and confirm the code is valid for the date of service in the Verify section.

Documentation check

The provider’s diagnostic statement
Codes are assigned from the provider’s documented diagnosis, not from clinical criteria, test values or a medication list (Guidelines I.A.19).
Acuity
Acute or chronic as documented; when both are documented and separate codes exist, both are reported with the acute code first (Guidelines I.B.8).
The conditions the Use Additional Code note names
Reported with this code when documented; a conditional instruction (“if applicable”, “if known”) applies only when the record supports it.
Any detail beyond this code’s title
What the record states that a more specific sibling code would capture — or its absence, which itself supports the unspecified code.

Official instructions as workflow

  • Excludes1 — check before selecting J42(7 notes)

    Coding workflow: If the documentation supports a condition named in this note, do not simply proceed with J42: the two are not reported together. The one exception is when the record shows the two conditions are unrelated to each other.

    CompareJ44.81, J44, J44.9, J41, J68.0

    See the official tabular notes · Guidelines I.A.12.a

  • Excludes2 — not part of J42(1 note)

    Coding workflow: The conditions named in this note are not included in J42. When the record documents both, both may be reported; the note is a boundary, not a prohibition.

    CompareE84

    See the official tabular notes · Guidelines I.A.12.b

  • Use Additional Code — after identifying J42(7 notes)

    Coding workflow: Check whether the documentation supports the additional code(s) the note names, and report them with J42 when it does. Where the instruction is conditional (“if applicable”, “if known”), it applies only when the record documents the condition.

    ReviewZ77.22, P96.81, Z87.891, Z57.31, F17, Z72.0

    See the official tabular notes · Guidelines I.A.13

  • Code Also — related condition(1 note)

    Coding workflow: Review the related condition when both are documented and the instruction applies. A Code Also note does not fix sequencing; the order follows the circumstances of the encounter.

    ReviewJ68.4

    See the official tabular notes · Guidelines I.A.17

Coding decision scenarios

Pattern scenarios for this code’s structure — decision rules, not clinical cases

Documentation: The provider documents the condition in the terms of this code’s title and records no further detail.

Coding question: Is a more specific sibling code supportable?

Path: Review the subcategory for a sibling that names the missing detail.

Reason: A more specific code needs documentation of the distinguishing element; without it the unspecified code is appropriate, and a provider query is the route to specificity (Guidelines I.A.9.b, I.B.18).

Documentation: Both the condition J42 describes and a condition named in its Excludes1 note are documented for the same encounter.

Coding question: Can both codes be reported?

Path: Review the Excludes1 note and the excluded code, and look for a provider statement on whether the two conditions are related.

Reason: Excludes1 means the two are not coded together; the exception is when the record shows the conditions are unrelated to each other (Guidelines I.A.12.a).

ReviewJ44.81, J44, J44.9, J41, J68.0

Documentation: A condition the Use Additional Code note names is documented.

Coding question: Is a second code reported with J42?

Path: Review the Use Additional Code note and the code it names.

Reason: The additional code is reported when the record documents the condition; a conditional instruction applies only when its condition is met (Guidelines I.A.13).

ReviewZ77.22, P96.81, Z87.891, Z57.31, F17, Z72.0

Every row is derived from this code’s own record — its title, tabular notes, 7th-character family and same-category siblings — with fixed MedCoder wording; nothing is inferred about a patient. The official notes and guideline text are in the sections each row links to, and they control.

Code Overview

Unspecified chronic bronchitis is a billable ICD-10-CM diagnosis code (J42).

MedCoder summary Summary composed by MedCoder from this code's official ICD-10-CM record. The tabular instructional notes themselves appear verbatim below.

Indexed Clinical Terms (11)

Official source data — entries quoted as published, in the Index’s own lookup phrasing

Clinical term phrases from the official ICD-10-CM Index to Diseases and Injuries that map to this code. These are alphabetic-index entries shown as the Index writes them — lookup phrasing, not necessarily the wording of a final diagnosis.

Decision Points

The directives on this code's own record, as a pre-claim checklist.

  1. 7 Use Additional Code instructions — report the named additional code(s) when the documentation supports them. See the Use Additional Code notes
  2. 1 Code Also note — a second code may apply; the guidelines leave its sequencing to the circumstances of the encounter. See the Code Also notes
  3. 7 Excludes1 entries — codes named there are generally not reported together with this code (Guidelines I.A.12.a). See the Excludes1 notes
  4. 1 Excludes2 entry — those conditions are not part of this code and may be reported additionally when documented. See the Excludes2 notes

Checklist rows are derived from this code's own official directives; the wording of each check is MedCoder editorial. The official notes themselves are in the sections each row links to.

Verify Before Coding

  • No Medicare Code Editor or MS-DRG Definitions Manual restrictions apply to this code.

From the code registry, the Medicare Code Editor, and the MS-DRG Definitions Manual. Check it against a full claim in Claim Check.

Relationships & Classification

MedCoder structured relationships — computed from published CMS and AHRQ datasets

Other codes that name J42 or its code family, from the CMS ICD-10-CM tabular instructional notes. Tabular-note edges are stored at the code family level that carries each note.

Referenced by 1 Excludes1 note: J37.1 — Chronic laryngotracheitis.

These codes’ tabular lists mark this diagnosis as mutually exclusive — not reported together unless the conditions are documented as unrelated.

Referenced by 4 Excludes2 notes: J04.1 — Acute tracheitis, J20 — Acute bronchitis, J41 — Simple and mucopurulent chronic bronchitis, J44 — Other chronic obstructive pulmonary disease.

These codes’ tabular lists name this diagnosis as distinct — both may be reported when both are documented.

Referenced by 1 Code Also instruction: J68.4 — Chronic respiratory conditions due to chemicals, gases, fumes and vapors.

These codes suggest coding this condition alongside when both are present.

MS-DRG Grouper Relationships (FY2026)

Potential MS-DRG participation — not a DRG assignment.

FY2026 MS-DRG: not on the CMS CC/MCC list — as a secondary diagnosis this code does not change MS-DRG severity for that release.

Named in the grouper logic of 3 MS-DRGs: DRG 190 (MDC 04), DRG 191 (MDC 04), DRG 192 (MDC 04).

From the CMS MS-DRG Definitions Manual (Appendices B and C). Actual DRG assignment depends on the complete claim.

Clinical classification (AHRQ CCSR):RSP008 — Chronic obstructive pulmonary disease and bronchiectasis (default).

Clinical Classifications Software Refined (CCSR) for ICD-10-CM Diagnoses. Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality.

Related Codes

Same CMS-HCC risk category (V28)

CMS maps these diagnoses to the same Hierarchical Condition Category (Chronic Obstructive Pulmonary Disease, Interstitial Lung Disorders, and Other Chronic Lung Disorders) for risk-adjusted payment.

B44.81 — Allergic bronchopulmonary aspergillosis, J41.0 — Simple chronic bronchitis, J41.1 — Mucopurulent chronic bronchitis, J41.8 — Mixed simple and mucopurulent chronic bronchitis, J43.0 — Unilateral pulmonary emphysema [MacLeod's syndrome], J43.1 — Panlobular emphysema, J43.2 — Centrilobular emphysema, J43.8 — Other emphysema, J43.9 — Emphysema, unspecified, J44.0 — Chronic obstructive pulmonary disease with (acute) lower respiratory infection, J44.1 — Chronic obstructive pulmonary disease with (acute) exacerbation, J44.81 — Bronchiolitis obliterans and bronchiolitis obliterans syndrome, J44.89 — Other specified chronic obstructive pulmonary disease, J44.9 — Chronic obstructive pulmonary disease, unspecified, J47.0 — Bronchiectasis with acute lower respiratory infection, J47.1 — Bronchiectasis with (acute) exacerbation, J47.9 — Bronchiectasis, uncomplicated, J60 — Coalworker's pneumoconiosis, J61 — Pneumoconiosis due to asbestos and other mineral fibers, J62.0 — Pneumoconiosis due to talc dust, +58 more

Related risk categories

These categories interact through CMS's HCC hierarchy — one can suppress the other's risk-adjustment weight when both are present on a claim.

Lung Transplant Status/Complications, Cystic Fibrosis, Idiopathic Pulmonary Fibrosis and Lung Involvement in Systemic Sclerosis, Severe Persistent Asthma

Same clinical category (CCSR)

AHRQ's Clinical Classifications Software groups these diagnoses under the same clinical category (Chronic obstructive pulmonary disease and bronchiectasis).

J41.0 — Simple chronic bronchitis, J41.1 — Mucopurulent chronic bronchitis, J41.8 — Mixed simple and mucopurulent chronic bronchitis, J43.0 — Unilateral pulmonary emphysema [MacLeod's syndrome], J43.1 — Panlobular emphysema, J43.2 — Centrilobular emphysema, J43.8 — Other emphysema, J43.9 — Emphysema, unspecified, J44.0 — Chronic obstructive pulmonary disease with (acute) lower respiratory infection, J44.1 — Chronic obstructive pulmonary disease with (acute) exacerbation, J44.81 — Bronchiolitis obliterans and bronchiolitis obliterans syndrome, J44.89 — Other specified chronic obstructive pulmonary disease, J44.9 — Chronic obstructive pulmonary disease, unspecified, J47.0 — Bronchiectasis with acute lower respiratory infection, J47.1 — Bronchiectasis with (acute) exacerbation, J47.9 — Bronchiectasis, uncomplicated, J4A.8 — Other chronic lung allograft dysfunction, J4A.9 — Chronic lung allograft dysfunction, unspecified

Same Index main term, other category

The ICD-10-CM Index to Diseases and Injuries files this code under the main terms “Bronchitis”, “Bronchorrhea”, “Tracheitis”, …; these codes share that main term but sit in a different category of the Tabular List.

J20.5 — Acute bronchitis due to respiratory syncytial virus (acute or subacute, due to, virus, respiratory syncytial), J20.6 — Acute bronchitis due to rhinovirus (acute or subacute, due to, virus, rhinovirus), J20.7 — Acute bronchitis due to echovirus (acute or subacute, due to, virus, echovirus), J20.8 — Acute bronchitis due to other specified organisms (viral NEC, acute or subacute), J20.9 — Acute bronchitis, unspecified (acute), J37.1 — Chronic laryngotracheitis (with, laryngitis, chronic), J40 — Bronchitis, not specified as acute or chronic, J41.0 — Simple chronic bronchitis (smokers'), J41.1 — Mucopurulent chronic bronchitis (fetid), J41.8 — Mixed simple and mucopurulent chronic bronchitis (mucopurulent, simple), J44.0 — Chronic obstructive pulmonary disease with (acute) lower respiratory infection (asthmatic, chronic, with, acute lower respiratory infection), J44.1 — Chronic obstructive pulmonary disease with (acute) exacerbation (asthmatic, chronic, with, exacerbation), J44.89 — Other specified chronic obstructive pulmonary disease (obstructive), J45.9 — Other and unspecified asthma (asthmatic), J45.901 — Unspecified asthma with (acute) exacerbation (allergic, with, exacerbation), J45.902 — Unspecified asthma with status asthmaticus (allergic, with, status asthmaticus), J45.909 — Unspecified asthma, uncomplicated (allergic), J47.0 — Bronchiectasis with acute lower respiratory infection (acute or subacute, with, bronchiectasis), J62.8 — Pneumoconiosis due to other dust containing silica (moulder's), J68.0 — Bronchitis and pneumonitis due to chemicals, gases, fumes and vapors (chemical), +19 more

Lab tests where this diagnosis supports Medicare coverage (NCD)

Medicare's National Coverage Determination (NCD) program lists this diagnosis as medical justification for these lab tests.

Blood Glucose Test

Contextual Map

Every relationship of J42 in one view: hierarchy, official tabular instructions in both directions, clinical classification, risk adjustment, MS-DRG participation, index terms and change history — each edge carrying the CMS source it derives from.

Run J42 with these 16 related codes in Claim Check

Hierarchy

Excludes1

Excludes2

  • E84 — Cystic fibrosis[Excludes2]: “cystic fibrosis (E84.-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026

Use Additional Code

Code Also

Referenced by Excludes1 notes

Referenced by Excludes2 notes

Referenced by Code Also instructions

Clinical classification (CCSR)

Risk adjustment (CMS-HCC)

  • HCC 280 — Chronic Obstructive Pulmonary Disease, Interstitial Lung Disorders, and Other Chronic Lung Disorders [CMS-HCC]— CMS-HCC V28 · 2026

MS-DRG Grouper

MDC crossing

  • MDC 04 — Diseases and Disorders of the Respiratory System[MDC crossing]: “Diseases and Disorders of the Respiratory System — the grouper's crossing between diagnoses and procedures: a principal diagnosis sets the MDC, and same-MDC procedures move the stay to its surgical DRGs. 3,998 same-MDC procedures group here; browse them on the MDC page.”— CMS MS-DRG Definitions Manual · FY2026

Index entries (11)

  • Bronchitis (diffuse) (fibrinous) (hypostatic) (infective) (membranous), chronic[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Bronchitis (diffuse) (fibrinous) (hypostatic) (infective) (membranous), chronic, with, tracheitis (chronic)[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Bronchitis (diffuse) (fibrinous) (hypostatic) (infective) (membranous), senile (chronic)[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Bronchitis (diffuse) (fibrinous) (hypostatic) (infective) (membranous), with, tracheitis (l5 years of age and above), chronic[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Bronchorrhea, chronic (infective) (purulent)[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Infection, infected, infective (opportunistic), trachea, chronic[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Pharyngotracheitis, chronic[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Tracheitis (catarrhal) (infantile) (membranous) (plastic) (septal) (suppurative) (viral), chronic[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • and 3 more

Change history (2)

Sources for this page

Codes, titles, notes, index terms and mappings on this page are transcribed from the datasets below. Relationships MedCoder computed and text MedCoder wrote are labelled where they appear.

Code, title, tabular notes and index terms Official source data
CMS/CDC ICD-10-CM FY2026 tabular list, index and tables, effective October 1, 2025 Release, file and checksum · Publisher’s page
Claim edits Official source data
CMS Definitions of Medicare Code Edits — v43.1 (April 2026) Release, file and checksum · Publisher’s page
Inpatient payment groups Official source data
CMS MS-DRG Definitions Manual (incl. Appendix B diagnosis index, Appendix C CC/MCC list, Appendix E procedure index) and IPPS Final Rule tables — v43 Release, file and checksum · Publisher’s page
Risk adjustment Official source data
2026 Mid-Year Final ICD-10 Mappings + Model Software (cms.gov/files/zip/2026-midyear-final-icd-10-mappings.zip, 2026-midyear-final-model-software.zip) — CMS-HCC V28, PY2026 mid-year final release Release, file and checksum · Publisher’s page
Change history and date-of-service validity Official source data
CMS ICD-10-CM release addenda, ingested release by release into the change ledger Release, file and checksum · Publisher’s page
Comparisons, relationships and the contextual map MedCoder structured relationship
Computed by MedCoder from the tabular notes and tables above; every derived relationship is marked as derived where it appears
Summary and FAQ answers MedCoder explanation
Written by MedCoder to explain the sources above: drafted with AI assistance, checked by a person against the release files, and labelled as MedCoder text where it appears. Not official text.

Labels on this page: Official source data · MedCoder structured relationship · MedCoder explanation. How to read the labels · All data sources and release dates

Cite this page

Reference this page in a research guide, syllabus or article. The release is included because code content changes each year.

MedCoder.ai. "J42 — Unspecified chronic bronchitis." ICD-10-CM FY2026. https://medcoder.ai/icd10/code/j42-unspecified-chronic-bronchitis

Change history

  • Upcoming · effective FY2027 — October 1, 2026
    Code Also note will be added
    , if applicable, chronic respiratory conditions due to chemicals, gases, fumes and vapors (J68.4)
    FY2027 changes
  • FY2016 — October 1, 2015
    In the code set at ICD-10-CM adoption
    Unspecified chronic bronchitis