J45.909 vs J67.8

J45.909 (Unspecified asthma, uncomplicated) compared with J67.8 (Hypersensitivity pneumonitis due to other organic dusts), from the official CMS tabular data. Do not report these codes together: the official tabular list marks them Excludes1. MedCoder-derived

Relationship

Conflict

Excludes1 conflict

J45.909

Unspecified asthma, uncomplicated

↔

J67.8

Hypersensitivity pneumonitis due to other organic dusts

Not coded here — these two are mutually exclusive.

“wood asthma (J67.8)”

An Excludes1 note means the two conditions cannot occur together, so the pair should not be reported for the same encounter. The sole exception is when the conditions are documented as unrelated to each other.

Source: CMS ICD-10-CM tabular instructional notes; ICD-10-CM Official Guidelines, Section I.A.12.a

Informational

Excludes2 relationship

J45.909

Unspecified asthma, uncomplicated

↔

J67.8

Hypersensitivity pneumonitis due to other organic dusts

Distinct conditions — both may be reported.

“lung diseases due to external agents (J60-J70)”

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: CMS ICD-10-CM tabular instructional notes

Can these codes be reported together?

No — do not report together. J45.909 carries an Excludes1 note covering J67.8: “wood asthma (J67.8)”

Sole exception: when the two conditions are documented as unrelated to each other (ICD-10-CM Official Guidelines, Section I.A.12.a).

Yes, when both are documented. J45.909 carries an Excludes2 note covering J67.8: “lung diseases due to external agents (J60-J70)”

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

Side by side

	J45.909Unspecified asthma, uncomplicated	J67.8Hypersensitivity pneumonitis due to other organic dusts
Billing status	Billable	Billable
Classification	J00-J99 — Diseases of the Respiratory System (J00-J99)	J00-J99 — Diseases of the Respiratory System (J00-J99)
Definition	Unspecified asthma, uncomplicated is a billable ICD-10-CM diagnosis code (J45.909).	Hypersensitivity pneumonitis due to other organic dusts is a billable ICD-10-CM diagnosis code (J67.8).
Includes	allergic (predominantly) asthma allergic bronchitis NOS allergic rhinitis with asthma atopic asthma	allergic alveolitis and pneumonitis due to inhaled organic dust and particles of fungal, actinomycetic or other origin Cheese-washer's lung Coffee-worker's lung Fish-meal worker's lung
Use additional code	code to identify: eosinophilic asthma (J82.83) exposure to environmental tobacco smoke (Z77.22)	—

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Derived from the official CMS ICD-10-CM tabular data (FY2026). Not billing advice; verify sequencing rules for the encounter. All data sources