F40.9 ICD-10-CM Code: Phobic anxiety disorder, unspecified
F40.9 is not a CMS-HCC payment code. MEAT criteria · RAF Calculator · HCC Buddy coding tools
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FY 2026 Apr update / Mental, Behavioral and Neurodevelopmental disorders (F01-F99) / Anxiety, dissociative, stress-related, somatoform and other nonpsychotic mental disorders (F40-F48)
F40.9
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidancePhobic anxiety disorder, unspecified
A phobic anxiety disorder where the specific type or nature of the phobia is not documented or specified.
Buddy Insight
Phobic anxiety disorder, unspecified, is used when a provider documents a phobia but does not specify the type or stimulus.
CMS-HCC V28
N/A—
Not mapped
CMS-HCC V24
HistoricalHistorical
Not used for CY2026 payment
ACA/HHS
N/A—
Not mapped
ESRD/PACE
N/A—
Not mapped
RXHCC
MappedHCC 133
Code-level coefficient reference
Code Book Path
Inclusion Terms
Official- Phobia NOS
- Phobic state NOS
Excludes 2
Official- symptoms, signs and abnormal clinical laboratory findings, not elsewhere classified (R00-R99)Inherited from F01-F99
Related Codes
Includes
Official- disorders of psychological developmentInherited from F01-F99
Excludes 1
OfficialNo Excludes 1 notes are included in this display for F40.9. Check the code and parent instructions in the Code Book.
Code First
OfficialNo Code First sequencing instructions are included in this display for F40.9. Check the code and parent instructions in the Code Book.
Use Additional
OfficialNo Use Additional Code instructions are included in this display for F40.9. Check the code and parent instructions in the Code Book.
Code Also
OfficialNo Code Also instructions are included in this display for F40.9. Check the code and parent instructions in the Code Book.
Buddy Documentation Tip
MEAT Support
Audit Caution
Common Mistakes
Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →
Is F40.9 an HCC code?
F40.9 has no mapping under the current CMS-HCC V28 community payment model. F40.9 has a separate mapping under the Part D RxHCC model (HCC 133 (Anxiety and Other Psychiatric Disorders)); the applicable result needs member context.
- Code
- F40.9
- Description
- Phobic anxiety disorder, unspecified
- HCC (V28)
- No CMS-HCC V28 mapping
- RAF reference coefficient
- —
- Billable
- Yes
- Payment year
- 2026
HCC Category Mapping
These are source-labeled model coefficients, not member totals. A category may still be removed by hierarchy or model cleanup rules. Weights are not directly comparable across models: CMS-HCC V28 and V24 use Community, Non-Dual, Aged; ESRD uses the dialysis continuing-enrollee model; RxHCC is the Part D continuing-enrollee, non-low-income, aged weight (a larger scale than CMS-HCC). ACA/HHS has no single weight — it varies by metal level. Actual per-patient RAF contribution depends on member context, hierarchy and cleanup rules, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains available for historical review.
Work F40.9 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →
MEAT review for F40.9
For F40.9, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule.
- MMonitor: signs, symptoms, disease progression, or lab trending documented in the note
- EEvaluate: test results, medication response, or physical findings reviewed by the provider
- AAssess: explicit mention in the assessment or plan with acknowledgment of status
- TTreat: medication, referral, procedure, therapy, or counseling tied to the diagnosis
Coder workflow notes
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What This Code Means
F40.9 is the ICD-10-CM diagnosis code for phobic anxiety disorder, unspecified. A phobic anxiety disorder where the specific type or nature of the phobia is not documented or specified. F40.9 sits in the ICD-10-CM chapter for mental, behavioral and neurodevelopmental disorders (f01-f99), within the section covering anxiety, dissociative, stress-related, somatoform and other nonpsychotic mental disorders (f40-f48).
F40.9 has no mapping under the current CMS-HCC V28 community payment model. F40.9 has a separate mapping under the Part D RxHCC model (HCC 133 (Anxiety and Other Psychiatric Disorders)); the applicable result needs member context. Do not assign V28 risk adjustment value from this page; verify the applicable model and payment year before using this code for risk adjustment.
Avoid using this code if the specific phobia can be identified; use more specific codes when possible.
HCC Buddy maintains structured V28 and V24 mapping, source-labeled coefficient references, and MEAT documentation criteria for F40.9 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Avoid using this code if the specific phobia can be identified; use more specific codes when possible
- •Request clarification from the provider about the specific phobic trigger for more accurate coding
Clinical Significance
Phobic anxiety disorder, unspecified, is used when a provider documents a phobia but does not specify the type or stimulus. This is the least specific code in the phobia category and should prompt a query for clarification whenever possible. It does not carry risk adjustment value under any HCC model.
Documentation Requirements
- ✓Provider documentation of a phobic disorder or phobia
- ✓Evidence of fear, anxiety, or avoidance behavior
- ✓Impact on functioning
- ✓Current treatment if applicable
- ✓Reason why the type of phobia cannot be further specified
Commonly Confused Codes
- •F40.8 (Other phobic anxiety disorders): Use F40.8 when the provider specifies the phobia but it does not match a named category; use F40.9 when truly unspecified
- •F41.9 (Anxiety disorder, unspecified): F40.9 is for phobic anxiety specifically; F41.9 is for non-phobic anxiety
- •F40.10 (Social phobia, unspecified): If social contexts are triggering the phobia, use the social phobia code