ICD-10 F16.21
Billable / Specific HCC v28: 55Hallucinogen dependence, in remission
About ICD-10-CM F16.21
ICD-10-CM code F16.21 represents Hallucinogen dependence, in remission. This is a billable/specific code in the Mental, Behavioral, and Neurodevelopmental chapter (block F16). The 2026 edition of ICD-10-CM F16.21 became effective on October 1, 2025.
Coding Tips for F16.21
Specialist guidance from the PayerReady Medical Coding Team. Specificity warnings, HCC capture rules, sequencing notes.
F16.21 is a CMS-HCC v28 risk-adjustment code (category 55). To count for the patient Risk Adjustment Factor (RAF), document the diagnosis with MEAT language each calendar year: Monitored, Evaluated, Assessed, Treated. A diagnosis on the problem list alone does not satisfy CMS RADV audit standards. Include the diagnosis in the assessment with current status and current treatment plan.
Inclusion Terms / Approximate Synonyms
Clinical terms and conditions classified under F16.21. Per CMS ICD-10-CM Tabular 2026.
- Other hallucinogen use disorder, moderate, in early remission
- Other hallucinogen use disorder, moderate, in sustained remission
- Other hallucinogen use disorder, severe, in early remission
- Other hallucinogen use disorder, severe, in sustained remission
- Phencyclidine use disorder, moderate, in early remission
- Phencyclidine use disorder, moderate, in sustained remission
- Phencyclidine use disorder, severe, in early remission
- Phencyclidine use disorder, severe, in sustained remission
Medicare Advantage HCC Impact
Capture this diagnosis annually for accurate risk adjustment. Missed HCC captures are the #1 revenue leak in Medicare Advantage risk programs.
Medicare LCD Coverage for F16.21
Local Coverage Determinations (LCDs) from CMS MACs that list F16.21 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 F16.21.
1 Cigna
5 Medicare
CPT Codes Commonly Billed with F16.21
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 F16.21 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 |
|---|---|---|
| F16.21 | 30453 | 00000 |
Flags format (5 digits): Approximate · No Map · Combination · Scenario · Choice List. Source: CMS 2017 GEMs (final version).
Codes Adjacent To F16.21
Other codes in section F10-F19 (Mental and behavioral disorders due to psychoactive substance use).
ICD-10 F16.21, Billing FAQ
Is ICD-10 code F16.21 billable? +
Yes, F16.21 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 F16.21? +
ICD-10 F16.21 includes: Other hallucinogen use disorder, moderate, in early remission; Other hallucinogen use disorder, moderate, in sustained remission; Other hallucinogen use disorder, severe, in early remission, and 5 more clinical synonyms.
Does F16.21 affect Medicare Advantage HCC risk adjustment? +
Yes. F16.21 maps to CMS-HCC v28 category 55. Capture this diagnosis annually for accurate Medicare Advantage risk score.
What ICD-9 codes does F16.21 map to? +
Per CMS GEMs, F16.21 maps to ICD-9 codes: 30453. 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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