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J45.909 ICD-10-CM Code: Unspecified asthma, uncomplicated

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

Coding at a Glance

Tabular directives
10 inclusion terms · 5 Excludes1 · 6 Excludes2 · 8 use-additional codes
Risk adjustment
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 202 — BRONCHITIS AND ASTHMA WITH CC/MCC (MDC 04)
  • MS-DRG 203 — BRONCHITIS AND ASTHMA 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.

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for J45.909 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 J45.909 itself; “inherited from” names the category or block whose note applies here.

Includes

Conditions the official ICD-10-CM tabular list includes under this code.

  • allergic (predominantly) asthma
  • allergic bronchitis NOS
  • allergic rhinitis with asthma
  • atopic asthma
  • extrinsic allergic asthma
  • hay fever with asthma
  • idiosyncratic asthma
  • intrinsic nonallergic asthma
  • nonallergic asthma

Source: inherited from J45

Inclusion Terms

Alternative terms the tabular list files under this code.

  • Asthma NOS

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.

Use Additional Code

Supplementary codes the tabular list directs you to add.

  • Use additional code to identify:
  • eosinophilic asthma (J82.83)
  • 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)

Source: inherited from J45

Coder workflow for J45.909

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

Before you code J45.909

  1. Unspecified does not mean incorrect. When the record gives no greater specificity, J45.909 may be the appropriate code. Check the record for detail that supports a more specific sibling — in this subcategory the siblings differ by the presence or absence of the associated condition. 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 J45.909. 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 — J45.909 is appropriate when the documentation goes no further.
  2. Does the documentation support a condition named in J45.909’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.

    ReviewJ69.8, J60, R06.2, J67.8, J68.0

Consider J45.909. Then work the Use Additional Code 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).
The associated condition or complication
Whether the associated condition the title names is documented; the “with” convention presumes some links, and a provider statement that the conditions are unrelated defeats it (Guidelines I.A.15).
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 J45.909(5 notes)

    Coding workflow: If the documentation supports a condition named in this note, do not simply proceed with J45.909: the two are not reported together. The one exception is when the record shows the two conditions are unrelated to each other.

    CompareJ69.8, J60, R06.2, J67.8, J68.0

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

  • Excludes2 — not part of J45.909(6 notes)

    Coding workflow: The conditions named in this note are not included in J45.909. When the record documents both, both may be reported; the note is a boundary, not a prohibition.

    CompareJ44.89, E84

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

  • Use Additional Code — after identifying J45.909(8 notes)

    Coding workflow: Check whether the documentation supports the additional code(s) the note names, and report them with J45.909 when it does. Where the instruction is conditional (“if applicable”, “if known”), it applies only when the record documents the condition.

    ReviewJ82.83, Z77.22, P96.81, Z87.891, Z57.31, F17

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

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 asthma, uncomplicated is a billable ICD-10-CM diagnosis code (J45.909).

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 (14)

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.

Official Coding Guidelines

Official source data — quoted verbatim from the CMS/NCHS Official Guidelines

Official source data — quoted verbatim from the CMS/NCHS Official Guidelines

Verbatim excerpts from the ICD-10-CM Official Guidelines for Coding and Reporting (CMS/NCHS) that govern this code.

Chapter 10: Diseases of the Respiratory System (J00-J99), U07.0 a. Chronic Obstructive Pulmonary Disease [COPD] and Asthma 1) Acute exacerbation of chronic obstructive bronchitis and asthma

The codes in categories J44 and J45 distinguish between uncomplicated cases and those in acute exacerbation. An acute exacerbation is a worsening or a decompensation of a chronic condition. An acute exacerbation is not equivalent to an infection superimposed on a chronic condition, though an exacerbation may be triggered by an infection.

Coding Notes

MedCoder editorial — not official ICD-10-CM text; reviewed against the cited source

What this code means

J45.909 is uncomplicated, unspecified asthma — the tabular’s slot for “Asthma NOS”. “Unspecified” means no documented severity class (the J45.2–J45.5 mild-intermittent through severe-persistent axis), and “uncomplicated” means neither acute exacerbation nor status asthmaticus is documented. It is the correct code exactly when the documentation supports nothing more specific — and a prompt to query the provider when it could.

Coding guidance

  • Check for a documented severity level first: mild intermittent, mild persistent, moderate persistent, and severe persistent asthma each have their own category, and J45.909 is only for records that state none.
  • An acute exacerbation is a documented worsening or decompensation of the asthma itself; the Chapter 10 guideline is explicit that a superimposed infection is not automatically an exacerbation, though it may trigger one.
  • Work the Use Additional Code list: exposure to environmental tobacco smoke (Z77.22), tobacco dependence (F17.-), tobacco use (Z72.0), history of tobacco dependence (Z87.891), occupational exposure (Z57.31), and eosinophilic asthma (J82.83) are all named on this code’s own record.
  • Asthma documented with COPD is classified to J44.89 — this code’s Excludes2 note routes asthma with chronic obstructive pulmonary disease, chronic asthmatic bronchitis, and chronic obstructive asthma there — and J44.89’s own Code Also note (“type of asthma, if applicable”) adds the documented asthma type code after it.
  • Wheezing alone is not asthma: wheezing NOS is R06.2, an Excludes1 on this code.

Decision-rule scenarios

Documentation: A visit note reads “asthma — continue albuterol” with no severity statement and no flare.

Coding question: Is a severity-specific code supportable?

Rule: No — the severity categories require a documented severity class, so the record as written supports only the unspecified, uncomplicated code. The deciding element is a provider-documented severity level; a query is the path to a more specific code.

Documentation: A patient with asthma presents with acute bronchitis and increased wheezing.

Coding question: Does the infection make this an asthma exacerbation?

Rule: Not by itself — an exacerbation is a documented worsening or decompensation of the asthma, and the guideline distinguishes it from a superimposed infection. The deciding element is whether the provider documents the asthma itself as exacerbated.

Scenarios state the decision rule, not a code assignment — code selection always follows the provider's documentation and the ICD-10-CM Official Guidelines.

Documentation checklist

  • Asthma type and severity class, when the provider can state one.
  • Presence or absence of acute exacerbation or status asthmaticus.
  • Tobacco exposure, use, or dependence, current or historical (the Use Additional Code list).
  • Any documented COPD overlap, which moves classification to J44.-.

Codes are assigned from provider documentation; a coder never infers a diagnosis.

Common mistakes

  • Defaulting to J45.909 when the record documents a severity class that supports a J45.2–J45.5 code.
  • Skipping the tobacco-status additional codes this code’s own note asks for.
  • Reporting J45.909 alone for asthma documented with COPD — the combination classifies to J44.89, with the asthma type coded also per J44.89’s Code Also note.
  • Coding asthma from wheezing alone — wheezing NOS is R06.2 (Excludes1).

Clinical context (coding perspective)

The severity axis mirrors how clinicians stage chronic asthma (intermittent versus persistent, by symptom frequency), which is why a severity code needs an explicit staging statement rather than a symptom description. “Uncomplicated” in the title is a term of art meaning without exacerbation or status asthmaticus, not a comment on the patient’s overall condition.

Written and reviewed by MedCoder against the official ICD-10-CM files; educational, not medical or billing advice. The official tabular notes and guidelines above take precedence in every case.

Decision Points

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

  1. 8 Use Additional Code instructions — report the named additional code(s) when the documentation supports them. See the Use Additional Code notes
  2. 5 Excludes1 entries — codes named there are generally not reported together with this code (Guidelines I.A.12.a). See the Excludes1 notes
  3. 6 Excludes2 entries — 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 J45.909 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 5 Excludes1 notes across 2 chapters: J30 — Vasomotor and allergic rhinitis, J40 — Bronchitis, not specified as acute or chronic (via J45.9.-), J40 — Bronchitis, not specified as acute or chronic, J98.01 — Acute bronchospasm (via J45.-), R06.2 — Wheezing (via J45.-).

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

Referenced by 13 Excludes2 notes: J20 — Acute bronchitis, J60 — Coalworker's pneumoconiosis (via J45.-), J60-J70 — Lung diseases due to external agents (J60-J70) (via J45.-), J61 — Pneumoconiosis due to asbestos and other mineral fibers (via J45.-), J62 — Pneumoconiosis due to dust containing silica (via J45.-), J63 — Pneumoconiosis due to other inorganic dusts (via J45.-), J64 — Unspecified pneumoconiosis (via J45.-), J65 — Pneumoconiosis associated with tuberculosis (via J45.-), J66 — Airway disease due to specific organic dust (via J45.-), J67 — Hypersensitivity pneumonitis due to organic dust (via J45.-), J68 — Respiratory conditions due to inhalation of chemicals, gases, fumes and vapors (via J45.-), J69 — Pneumonitis due to solids and liquids (via J45.-), J70 — Respiratory conditions due to other external agents (via J45.-).

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

Referenced by 1 Code First instruction: F54 — Psychological and behavioral factors associated with disorders or diseases classified elsewhere (via J45.-).

Each of these codes carries a Code First note naming this condition — when that code is reported, THIS code is sequenced first, ahead of it.

Referenced by 1 Code Also instruction: J44 — Other chronic obstructive pulmonary disease (via J45.-).

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 2 MS-DRGs: DRG 202 (MDC 04), DRG 203 (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):RSP009 — Asthma (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 clinical category (CCSR)

AHRQ's Clinical Classifications Software groups these diagnoses under the same clinical category (Asthma).

J45.20 — Mild intermittent asthma, uncomplicated, J45.21 — Mild intermittent asthma with (acute) exacerbation, J45.22 — Mild intermittent asthma with status asthmaticus, J45.30 — Mild persistent asthma, uncomplicated, J45.31 — Mild persistent asthma with (acute) exacerbation, J45.32 — Mild persistent asthma with status asthmaticus, J45.40 — Moderate persistent asthma, uncomplicated, J45.41 — Moderate persistent asthma with (acute) exacerbation, J45.42 — Moderate persistent asthma with status asthmaticus, J45.50 — Severe persistent asthma, uncomplicated, J45.51 — Severe persistent asthma with (acute) exacerbation, J45.52 — Severe persistent asthma with status asthmaticus, J45.901 — Unspecified asthma with (acute) exacerbation, J45.902 — Unspecified asthma with status asthmaticus, J45.990 — Exercise induced bronchospasm, J45.991 — Cough variant asthma, J45.998 — Other asthma

Same Index main term, other category

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

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), J42 — Unspecified chronic bronchitis (senile), J43.9 — Emphysema, unspecified (airway, with, emphysema), 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), J44.9 — Chronic obstructive pulmonary disease, unspecified (airway, chronic), J47.0 — Bronchiectasis with acute lower respiratory infection (acute or subacute, with, bronchiectasis), J47.1 — Bronchiectasis with (acute) exacerbation (airway, with, bronchiectasis, with, exacerbation), J47.9 — Bronchiectasis, uncomplicated (airway, with, bronchiectasis), J60 — Coalworker's pneumoconiosis (miner's), J62.8 — Pneumoconiosis due to other dust containing silica (moulder's), J64 — Unspecified pneumoconiosis (pneumoconiotic NEC), J67.8 — Hypersensitivity pneumonitis due to other organic dusts (wood), J67.9 — Hypersensitivity pneumonitis due to unspecified organic dust (airway, with, allergic alveolitis), J68.0 — Bronchitis and pneumonitis due to chemicals, gases, fumes and vapors (chemical), J68.3 — Other acute and subacute respiratory conditions due to chemicals, gases, fumes and vapors (due to, inhalation of fumes), +276 more

Contextual Map

Every relationship of J45.909 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 J45.909 with these 16 related codes in Claim Check

Hierarchy

Excludes2 (11)

Referenced by Excludes1 notes

Referenced by Excludes2 notes (13)

Referenced by Code First instructions

Referenced by Code Also instructions

Clinical classification (CCSR)

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 (14)

  • Asthma, asthmatic (bronchial) (catarrh) (spasmodic)[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Asthma, asthmatic (bronchial) (catarrh) (spasmodic), allergic extrinsic[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Asthma, asthmatic (bronchial) (catarrh) (spasmodic), childhood[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Asthma, asthmatic (bronchial) (catarrh) (spasmodic), late-onset[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Asthma, asthmatic (bronchial) (catarrh) (spasmodic), mixed[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Asthma, asthmatic (bronchial) (catarrh) (spasmodic), nonallergic (intrinsic)[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Asthma, asthmatic (bronchial) (catarrh) (spasmodic), predominantly allergic[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Bronchitis (diffuse) (fibrinous) (hypostatic) (infective) (membranous), allergic (acute)[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • and 6 more

Nearest codes (25)

Change history

  • FY2016 — In the code set at ICD-10-CM adoption [Change history]— CMS release files (code change ledger) · icd10cm-fy2016

Common coding questions

When is J45.909 the right asthma code?

When the documentation says “asthma” and nothing more codable: no severity class (the mild-intermittent through severe-persistent categories each have their own codes) and no exacerbation or status asthmaticus. “Asthma NOS” is this code’s own inclusion term — it is the honest floor, and a severity query is the path off it.

Is J45.909 reported when the patient also has COPD?

Not by itself. Asthma documented with COPD classifies to J44.89 — J45.909’s Excludes2 note routes asthma with chronic obstructive pulmonary disease and chronic obstructive asthma there — and J44.89’s own Code Also note adds the documented type of asthma (J45.-) after it. See J44.89 vs J45.909.

What makes an encounter “uncomplicated” for J45.909?

No acute exacerbation and no status asthmaticus. The Chapter 10 guideline defines an exacerbation as a worsening or decompensation of the chronic condition and states it is not equivalent to an infection superimposed on it — so bronchitis alongside stable asthma does not, on its own, move the encounter off the uncomplicated code.

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
Coding guidelines Official source data
ICD-10-CM Official Guidelines for Coding and Reporting (FY2026), quoted by section 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
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, coding notes, decision checklist 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. "J45.909 — Unspecified asthma, uncomplicated." ICD-10-CM FY2026. https://medcoder.ai/icd10/code/j45.909-unspecified-asthma-uncomplicated

Change history

  • FY2016 — October 1, 2015
    In the code set at ICD-10-CM adoption
    Unspecified asthma, uncomplicated

No changes since FY2016 — additions, deletions, description changes and billable-status changes are tracked through FY2027 (effective October 1, 2026), and none are recorded for this code. Note changes are tracked from FY2027 only.

Nearest Codes in This Family

Official ICD-10-CM classifications closest to J45.909 in its code family, with their registry titles.

View all codes in the J45 family