2026 ICD-10-CM Diagnosis Code F31.81Bipolar II disorder

ICD-10-CM Codes›F01–F99›F30-F39›F31

ICD-10-CM F31.81
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

F31.81 is a billable ICD-10-CM diagnosis code for bipolar II disorder. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026). In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Bipolar and related disorders.

Code Identity

ICD-10-CM Code
F31.81
Billable Status
Yes — Valid for Submission
Code Describes
Bipolar II disorder
Short Description
Bipolar II disorder
Same as the full description in the CMS dataset.
Parent Code
F31.8
Other bipolar disorders

Code Classification

ChapterF01–F99Mental and behavioural disorders
SectionF30-F39Mood [affective] disorders
CategoryF31Bipolar disorder
This CodeF31.81Bipolar II disorder

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Bipolar disorder in full remission
  • Bipolar disorder in partial remission
  • Bipolar II disorder
  • Bipolar II disorder, most recent episode hypomanic
  • Bipolar II disorder, most recent episode major depressive
  • Bipolar II disorder, most recent episode major depressive with atypical features
  • Bipolar II disorder, most recent episode major depressive with catatonic features
  • Bipolar II disorder, most recent episode major depressive with melancholic features
  • Bipolar II disorder, most recent episode major depressive with postpartum onset
  • Bipolar type II disorder currently in full remission
  • Chronic bipolar II disorder, most recent episode major depressive
  • Mild bipolar disorder
  • Mild bipolar II disorder, most recent episode major depressive
  • Moderate bipolar disorder
  • Moderate bipolar II disorder, most recent episode major depressive
  • Mood disorder in partial remission
  • Rapid cycling bipolar II disorder
  • Severe bipolar disorder without psychotic features
  • Severe bipolar II disorder
  • Severe bipolar II disorder, most recent episode major depressive with psychotic features
  • Severe bipolar II disorder, most recent episode major depressive with psychotic features, mood-congruent
  • Severe bipolar II disorder, most recent episode major depressive with psychotic features, mood-incongruent
  • Severe bipolar II disorder, most recent episode major depressive without psychotic features
  • Severe bipolar II disorder, most recent episode major depressive, in full remission
  • Severe bipolar II disorder, most recent episode major depressive, in partial remission
  • Severe bipolar II disorder, most recent episode major depressive, in remission

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Inclusion Terms

  • Bipolar disorder, type 2

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Disorder(of)
      • bipolar (I) (seasonal) (type 1)
        • II (type 2)

Clinical ClassificationClinical

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

CCSR MBD003
Bipolar and related disorders
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Bipolar Disorder

Bipolar disorder is a mood disorder that can cause intense mood swings:

The full article covers:

  • What is bipolar disorder?
  • What are the types of bipolar disorder?
  • What causes bipolar disorder?
  • Who is at risk for bipolar disorder?
  • What are the symptoms of bipolar disorder?
  • How is bipolar disorder diagnosed?
  • What are the treatments for bipolar disorder?

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert F31.81 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
296.89 Bipolar disorder NEC
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About F31.81Overview

Is F31.81 (Other bipolar disorders) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report bipolar II disorder on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What is the ICD-9 equivalent of F31.81?

Under the General Equivalence Mappings, bipolar II disorder converts to ICD-9-CM 296.89 (bipolar disorder NEC). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:

  • The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
  • The condition places limitations on self-care, independent living, and social interactions.