ICD-10 F09
Billable / SpecificUnspecified mental disorder due to known physiological condition
About ICD-10-CM F09
ICD-10-CM code F09 represents Unspecified mental disorder due to known physiological condition. This is a billable/specific code in the Mental, Behavioral, and Neurodevelopmental chapter (block F09). The 2026 edition of ICD-10-CM F09 became effective on October 1, 2025.
Inclusion Terms / Approximate Synonyms
Clinical terms and conditions classified under F09. Per CMS ICD-10-CM Tabular 2026.
- Mental disorder NOS due to known physiological condition
- Organic brain syndrome NOS
- Organic mental disorder NOS
- Organic psychosis NOS
- Symptomatic psychosis NOS
Type 1 Excludes
Pure excludes, these codes can never be coded together with F09. The conditions are mutually exclusive (e.g., congenital vs acquired forms).
- mild neurocognitive disorder due to known physiological condition (F06.7-)
- psychosis NOS (F29)
Coding Notes
Code First
- the underlying physiological condition
Medicare LCD Coverage for F09
Local Coverage Determinations (LCDs) from CMS MACs that list F09 as a covered diagnosis.
Showing top 10 of 208 total . Click a CPT for full coverage scope.
Commercial Payer Coverage
Coverage policies from major commercial payers referencing F09.
1 Cigna
5 Medicare
CPT Codes Commonly Billed with F09
Procedures frequently paired with this diagnosis based on PayerReady's Dx↔Px linkage data.
We don't have CPT pairings indexed for this specific code yet. Use the CPT search above to find common procedures, or check your payer's published medical policy for code-specific guidance.
Convert F09 to ICD-9-CM
Per CMS General Equivalence Mappings (GEMs), useful for legacy data review and historical claim analysis.
| ICD-10 | ICD-9 | Mapping Flags |
|---|---|---|
| F09 | 3109 | 10000 |
Flags format (5 digits): Approximate · No Map · Combination · Scenario · Choice List. Source: CMS 2017 GEMs (final version).
Codes Adjacent To F09
Other codes in section F01-F09 (Mental disorders due to known physiological conditions).
ICD-10 F09, Billing FAQ
Is ICD-10 code F09 billable? +
Yes, F09 is a billable ICD-10-CM code that can appear as a primary or secondary diagnosis on claims.
What other names or terms map to F09? +
ICD-10 F09 includes: Mental disorder NOS due to known physiological condition; Organic brain syndrome NOS; Organic mental disorder NOS, and 2 more clinical synonyms.
What codes are Type 1 Excludes for F09? +
Type 1 Excludes (never code together with F09): mild neurocognitive disorder due to known physiological condition (F06.7-); psychosis NOS (F29)
What ICD-9 codes does F09 map to? +
Per CMS GEMs, F09 maps to ICD-9 codes: 3109. Useful for legacy data review and historical claim analysis.
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Reviewed by the PayerReady Medical Coding Team
Verified against the CMS 2026 code set on May 31, 2026.
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