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ICD-10-CM 2027 diagnosis code

F16.91Hallucinogen use, unspecified, in remission

✓ Billable / specific

F16.91 is a valid, billable ICD-10-CM code for hallucinogen use, unspecified, in remission. It can be reported on claims for dates of service from October 1, 2026 – September 30, 2027.

Code last changed in FY2023 (effective October 1, 2022). Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data

About F16.91

F16.91 is the ICD-10-CM diagnosis code for hallucinogen use, unspecified, in remission. It belongs to category F16 (hallucinogen related disorders), block F10-F19 (mental and behavioral disorders due to psychoactive substance use) and chapter 5 (mental, Behavioral and Neurodevelopmental disorders). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.

Within F16.9 (hallucinogen use, unspecified), F16.91 is specifically for hallucinogen use, unspecified, in remission. Related codes cover uncomplicated (F16.90), with intoxication (F16.92), with hallucinogen-induced mood disorder (F16.94), with hallucinogen-induced psychotic disorder (F16.95), with other specified hallucinogen-induced disorder (F16.98) and with unspecified hallucinogen-induced disorder (F16.99).

It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.

In MS-DRG v44.0, it is part of the grouping logic for DRG 894 (Alcohol, Drug Abuse or Dependence, Left AMA, relative weight 0.6275), DRG 895 (Alcohol, Drug Abuse or Dependence with Rehabilitation Therapy, relative weight 1.4266), DRG 896 (Alcohol, Drug Abuse or Dependence without Rehabilitation Therapy with MCC, relative weight 1.6617) and DRG 897 (Alcohol, Drug Abuse or Dependence without Rehabilitation Therapy without MCC, relative weight 0.8584), in MDC 20 (Alcohol/Drug Use and Alcohol/Drug Induced Organic Mental Disorders), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.

It was added in FY2023, effective October 1, 2022.

Notes that apply from higher levels

Instructions written at a parent level also apply to F16.91.

› From F16.9 Hallucinogen use, unspecified
Excludes1
› From F16 Hallucinogen related disorders
Includes
  • ecstasy
  • PCP
  • phencyclidine

Broader instructions also apply from Chapter 5: Mental, Behavioral and Neurodevelopmental disorders.

Alphabetic index entries

1 entries

Terms in the official ICD-10-CM index that lead to F16.91.

MS-DRG v44.0 grouping

All DRGs →

Inpatient MS-DRGs this diagnosis can group to, as the principal or a secondary diagnosis, depending on the rest of the claim.

Code history

  1. 2016
  2. 2017
  3. 2018
  4. 2019
  5. 2020
  6. 2021
  7. 2022
  8. 2023
  9. 2024
  10. 2025
  11. 2026
  12. 2027
  • FY2023 (effective 10/1/2022): Added
  • No changes since FY2023.

Common questions about F16.91

Is F16.91 billable?

Yes. F16.91 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).

Can F16.91 be used as a principal diagnosis?

Yes. The Medicare Code Editor doesn't restrict F16.91 as a principal diagnosis.

Is F16.91 a CC or MCC?

No. F16.91 is neither a CC nor an MCC under MS-DRG v44.0.

What DRG does F16.91 group to?

F16.91 is used in the MS-DRG v44.0 logic for MS-DRG 894 (Alcohol, Drug Abuse or Dependence, Left AMA), MS-DRG 895 (Alcohol, Drug Abuse or Dependence with Rehabilitation Therapy), MS-DRG 896 (Alcohol, Drug Abuse or Dependence without Rehabilitation Therapy with MCC) and MS-DRG 897 (Alcohol, Drug Abuse or Dependence without Rehabilitation Therapy without MCC). Which one applies depends on whether it is the principal diagnosis and on the rest of the claim.