2027 ICD-10-CM Diagnosis Code F16.91Hallucinogen use, unspecified, in remission

ICD-10-CM Codes›F01–F99›F10-F19›F16

ICD-10-CM F16.91
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

F16.91 is a billable ICD-10-CM diagnosis code for hallucinogen use, unspecified, in remission. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 894 through 897. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Mental and substance use disorders in remission.

Code Identity

ICD-10-CM Code
F16.91
Billable Status
Yes — Valid for Submission
Code Describes
Hallucinogen use, unspecified, in remission
Short Description
Hallucinogen use, unspecified, in remission
Same as the full description in the CMS dataset.
Parent Code
F16.9
Hallucinogen use, unspecified

Code Classification

ChapterF01–F99Mental and behavioural disorders
SectionF10-F19Mental and behavioral disorders due to psychoactive substance use
CategoryF16Hallucinogen related disorders
This CodeF16.91Hallucinogen use, unspecified, in remission

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to F16.91: its own notes plus those printed at F16.9, F16, and Chapter 5. A note printed at a category, block or chapter applies to every code under it.

Includes

Further defines, or gives examples of, the content of the category.

From F16 Hallucinogen related disorders applies to 40 codes
  • ecstasy
  • PCP
  • phencyclidine
From Chapter 5 (F01-F99) Mental and behavioural disorders applies to 872 codes
  • disorders of psychological development

Excludes1

Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.

From F16.9 Hallucinogen use, unspecified applies to 13 codes

Excludes2

Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.

From Chapter 5 (F01-F99) Mental and behavioural disorders applies to 872 codes
  • symptoms, signs and abnormal clinical laboratory findings, not elsewhere classified (R00-R99)

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name F16.91, its category, or a range that includes it.

Excludes1 2

These codes carry an Excludes1 note naming F16.91: they are not reported together with it, unless the two conditions are unrelated.

  • F16.1 Hallucinogen abuse
    hallucinogen use, unspecified (F16.9-) names F16.9-, which includes this code
  • F16.2 Hallucinogen dependence
    hallucinogen use, unspecified (F16.9-) names F16.9-, which includes this code

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR MBD026
Mental and substance use disorders in remission
Default principal diagnosis: inpatient Yes · outpatient Yes

Code History & ChangesHistory

Replacement F16.91 replaces the following previously assigned code(s):

  • F16.90 - Hallucinogen use, unspecified, uncomplicated
FY 2023AddedAdded to the ICD-10-CM code setEffective October 1, 2022.
FY 2024–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About F16.91Overview

What is the ICD-10 code for hallucinogen use, unspecified, in remission?

The ICD-10-CM code for hallucinogen use, unspecified, in remission is F16.91 (sometimes written as F1691). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is F16.91 (Hallucinogen use, unspecified) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report hallucinogen use, unspecified, in remission on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does F16.91 group to?

When hallucinogen use, unspecified, in remission is the principal diagnosis on an inpatient stay, it groups to MS-DRG 894, 897, 895, 896, with relative weights from 0.6272 to 1.6610 depending on complications. Higher weights mean higher Medicare reimbursement.

Can F16.91 be reported with a code from F16.1?

Not as a rule. The Excludes1 note at F16.9, which applies to F16.91, lists "hallucinogen abuse (F16.1-)". An Excludes1 note means the excluded code is never reported together with this one; the only exception is when the two conditions are unrelated to each other (Official Guidelines, Section I.A.12.a).