ICD-10 F43.9
Billable / SpecificReaction to severe stress, unspecified
About ICD-10-CM F43.9
ICD-10-CM code F43.9 represents Reaction to severe stress, unspecified. This is a billable/specific code in the Mental, Behavioral, and Neurodevelopmental chapter (block F43). The 2026 edition of ICD-10-CM F43.9 became effective on October 1, 2025.
Inclusion Terms / Approximate Synonyms
Clinical terms and conditions classified under F43.9. Per CMS ICD-10-CM Tabular 2026.
- Trauma and stressor-related disorder, NOS
- Unspecified trauma and stressor-related disorder
Medicare LCD Coverage for F43.9
Local Coverage Determinations (LCDs) from CMS MACs that list F43.9 as a covered diagnosis.
Showing top 10 of 81 total . Click a CPT for full coverage scope.
Commercial Payer Coverage
Coverage policies from major commercial payers referencing F43.9.
1 Cigna
4 Medicare
CPT Codes Commonly Billed with F43.9
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 F43.9 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 |
|---|---|---|
| F43.9 | 3099 | 10000 |
Flags format (5 digits): Approximate · No Map · Combination · Scenario · Choice List. Source: CMS 2017 GEMs (final version).
Codes Adjacent To F43.9
Other codes in section F40-F48 (Anxiety, dissociative, stress-related, somatoform and other nonpsychotic mental disorders).
ICD-10 F43.9, Billing FAQ
Is ICD-10 code F43.9 billable? +
Yes, F43.9 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 F43.9? +
ICD-10 F43.9 includes: Trauma and stressor-related disorder, NOS; Unspecified trauma and stressor-related disorder.
What ICD-9 codes does F43.9 map to? +
Per CMS GEMs, F43.9 maps to ICD-9 codes: 3099. 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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