F16.21 — Hallucinogen dependence, in remission
F16.21 is a billable, specific ICD-10-CM code for hallucinogen dependence, in remission. It is valid for submission on a claim.
Inclusion terms
Alternative wordings a physician may use in the chart for this same code.
- 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
Excludes1 inherited from the categories above F16.21
These are not written on F16.21, but they bind it: a note on a category applies to every code beneath it. Billing F16.21 with anything listed here is a denial.
Risk adjustment
F16.21 risk-adjusts. Under the CMS-HCC V28 model it maps to this category:
- HCC 137 Drug Use Disorder, Moderate/Severe, or Drug Use with Non-Psychotic Complications0.424 RAF
Coefficient shown for the Community Non-dual Aged segment. A higher HCC in the same hierarchy will suppress this one, so capturing it does not always add score.
Medicare coverage
F16.21 is named in 13 Medicare coverage policies — 10 listing it as supporting medical necessity, and 3 listing it as NOT covered. Which of them applies to you depends on your Medicare contractor, and coverage genuinely differs by state.
- A52434Health and Behavior Assessment/Intervention – Medical Policy Articlenot covered
- A56865Billing and Coding: Psychiatric Inpatient Hospitalizationnot covered
- A59718Billing and Coding: Opioid Treatment Programsnot covered
- A56645Billing and Coding: Controlled Substance Monitoring and Drugs of Abuse Testing
How F16.21 is indexed
Coders do not find codes by browsing the tabular list — they look them up in the alphabetic index, under the word the physician wrote. These are the index entries that lead here, so you can see which chart wordings map to F16.21.
- Dependence›drug NEC›hallucinogen›in remission
- Disorder›hallucinogen use›moderate or severe›in remission(early) (sustained)
- Disorder›phencyclidine use›moderate or severe›in remission(early) (sustained)
Code history
F16.21 has not changed since FY2024 — no addition, revision or deletion across the three most recent ICD-10-CM releases.
Related codes at this level
Codes that share F16.2. If F16.21 is not quite right, the correct code is usually one of these.
- F16.20Hallucinogen dependence, uncomplicated
- F16.22Hallucinogen dependence with intoxication
- F16.24Hallucinogen dependence with hallucinogen-induced mood disorder
- F16.25Hallucinogen dependence with hallucinogen-induced psychotic disorder
- F16.28Hallucinogen dependence with other hallucinogen-induced disorder
- F16.29Hallucinogen dependence with unspecified hallucinogen-induced disorder
Questions about F16.21
- Is F16.21 a billable ICD-10-CM code?
- Yes. F16.21 is a billable, specific ICD-10-CM code and is valid for submission on a claim.
- Where does F16.21 sit in the tabular list?
- Mental, Behavioral and Neurodevelopmental disorders (F01-F99), in the block Mental and behavioral disorders due to psychoactive substance use (F10-F19).
- What cannot be coded together with F16.21?
- F16.21 carries Excludes1 notes, which means the conditions they list can never be coded together with it on the same encounter. Some are written on the categories above F16.21 (F16.2) and apply to it just the same.