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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 v43.0, 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.

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.

Official Tabular Instructional Notes

Sequencing, inclusion, and exclusion notes published for J45.909 in the official ICD-10-CM tabular list.

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

Indexed Clinical Terms (14)

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.

  • Asthma, asthmatic (bronchial) (catarrh) (spasmodic)
  • Asthma, asthmatic (bronchial) (catarrh) (spasmodic), allergic extrinsic
  • Asthma, asthmatic (bronchial) (catarrh) (spasmodic), childhood
  • Asthma, asthmatic (bronchial) (catarrh) (spasmodic), late-onset
  • Asthma, asthmatic (bronchial) (catarrh) (spasmodic), mixed
  • Asthma, asthmatic (bronchial) (catarrh) (spasmodic), nonallergic (intrinsic)
  • Asthma, asthmatic (bronchial) (catarrh) (spasmodic), predominantly allergic
  • Bronchitis (diffuse) (fibrinous) (hypostatic) (infective) (membranous), allergic (acute)
  • Dyspnea (nocturnal) (paroxysmal), asthmatic (bronchial)
  • Dyspnea (nocturnal) (paroxysmal), asthmatic (bronchial), with, bronchitis
  • Fever (inanition) (of unknown origin) (persistent) (with chills) (with rigor), hay (allergic), with asthma (bronchial)
  • IgE asthma
  • Obstruction, obstructed, obstructive, airway, with, asthma
  • Rhinitis (atrophic) (catarrhal) (chronic) (croupous) (fibrinous) (granulomatous) (hyperplastic) (hypertrophic) (membranous) (obstructive) (purulent) (suppurative) (ulcerative), allergic, with asthma

Official Coding 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

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.

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.

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.

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.

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

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)

Not on the CMS CC/MCC list — as a secondary diagnosis this code does not change MS-DRG severity.

Potential MS-DRG participation — not a DRG assignment.

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.

Hierarchy

Excludes2

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.”

Index entries (14)

  • Asthma, asthmatic (bronchial) (catarrh) (spasmodic)[Index term]
  • Asthma, asthmatic (bronchial) (catarrh) (spasmodic), allergic extrinsic[Index term]
  • Asthma, asthmatic (bronchial) (catarrh) (spasmodic), childhood[Index term]
  • Asthma, asthmatic (bronchial) (catarrh) (spasmodic), late-onset[Index term]
  • Asthma, asthmatic (bronchial) (catarrh) (spasmodic), mixed[Index term]
  • Asthma, asthmatic (bronchial) (catarrh) (spasmodic), nonallergic (intrinsic)[Index term]
  • Asthma, asthmatic (bronchial) (catarrh) (spasmodic), predominantly allergic[Index term]
  • Bronchitis (diffuse) (fibrinous) (hypostatic) (infective) (membranous), allergic (acute)[Index term]
  • and 6 more

Nearest codes (25)

Change history

  • FY2016 — In the code set at ICD-10-CM adoption [Change history]

Frequently Asked Questions (FAQ) & Clinical Guidance

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.

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