F99-F99
Medium Complexity

Unspecified mental disorder

Primary Specialty: Psychiatry
Last Updated: 2025-09-09

ICD-10 Codes (0)

0 billable
0 category headers

No codes found matching your search

Updates & Changes

FY 2026 Updates

Current Year

New Codes (2)

F10.288
Alcohol use disorder with other alcohol-induced disorder, severe
F11.288
Opioid use disorder with other opioid-induced disorder, severe

Revised Codes (2)

F11.10
Opioid abuse, uncomplicated - updated to align with DSM-5-TR criteria
F12.10
Cannabis abuse, uncomplicated - updated terminology and criteria

Deleted Codes

No codes deleted in this range for FY 2026

Historical Changes

  • FY 2025: Routine maintenance updates with minor terminology clarifications
  • FY 2024: Enhanced specificity requirements for certain code ranges
  • FY 2023: Updated documentation guidelines for improved clarity

Upcoming Changes

  • Proposed updates pending review by Coordination and Maintenance Committee
  • Under consideration: Enhanced digital health integration codes

Implementation Guidance

  • Review all FY 2026 updates for F99-F99 codes before implementation
  • Always verify the most current codes in the ICD-10-CM manual
  • Ensure clinical documentation supports the selected diagnosis codes
  • +3 more guidance items...

Range Overview

high priority

The ICD-10 code range F99-F99, Unspecified mental disorder, is used when a patient presents with a mental disorder, but the specific condition is not documented. This code is typically a last resort, used when the clinician has not provided enough information to assign a more specific code. It covers all mental disorders, not classified elsewhere.

Key Usage Points:

  • This code is used when the specific mental disorder is not specified in the documentation.
  • F99 should not be used if a more specific code can be assigned.
  • F99 is not used for temporary mental disorders due to known physiological conditions.
  • This code is not used for mental retardation (F70-F79).
  • F99 should not be used if the patient is in remission.

Coding Guidelines

When to Use:

  • When a patient presents with symptoms of a mental disorder, but the specific condition is not documented.
  • When the patient's mental disorder is known, but not classified elsewhere in ICD-10.
  • When the patient's mental disorder is unspecified due to lack of information in the medical record.
  • When the patient's mental disorder is unspecified due to inconclusive diagnostic results.

When NOT to Use:

  • When the patient's mental disorder is specified in the documentation.
  • When the patient's mental disorder is temporary and due to a known physiological condition.
  • When the patient's mental disorder is mental retardation.
  • When the patient's mental disorder is in remission.

Code Exclusions

Always verify exclusions with the patient's medical record and the latest version of ICD-10.

Documentation Requirements

Documentation for F99 should include a clear description of the patient's symptoms and any diagnostic tests performed. The clinician should also document why a more specific diagnosis could not be made.

Clinical Information:

  • Description of the patient's symptoms
  • Results of any diagnostic tests
  • Reason why a more specific diagnosis could not be made
  • Any relevant medical history
  • Any relevant family history

Supporting Evidence:

  • Clinical notes
  • Lab reports
  • Imaging reports
  • Consultation notes
Good Documentation Example:

Patient presents with symptoms of a mental disorder. Diagnostic tests were inconclusive. A more specific diagnosis could not be made at this time.

Poor Documentation Example:

Patient has a mental disorder.

Common Documentation Errors:

  • Not documenting the reason why a more specific diagnosis could not be made
  • Not including enough detail about the patient's symptoms
  • Not including results of diagnostic tests

Range Statistics

Total Codes
0
Billable
Complexity:
Medium
Primary Use:Clinical Documentation
Chapter:5

Coding Complexity

Medium
Complexity Rating

Coding for F99 can be complex due to the need to determine when to use this code versus a more specific code. Coders must also understand the exclusions for F99 and verify the information in the patient's medical record. Additionally, keeping up to date with changes to ICD-10 can add to the complexity.

Key Factors:
  • Determining when to use F99 versus a more specific code
  • Understanding the exclusions for F99
  • Verifying the information in the patient's medical record
  • Keeping up to date with changes to ICD-10

Specialty Focus

F99 is most commonly used by psychiatrists and psychologists. It may also be used by primary care providers when a patient presents with symptoms of a mental disorder, but a more specific diagnosis cannot be made.

Primary Specialties:
Psychiatry
70%
Psychology
20%
Primary Care
10%
Clinical Scenarios:
  • A patient presents with symptoms of a mental disorder, but diagnostic tests are inconclusive.
  • A patient presents with symptoms of a mental disorder, but the specific condition is not documented.
  • A patient presents with symptoms of a mental disorder, but the clinician is unable to make a more specific diagnosis.
  • A patient presents with symptoms of a mental disorder, but the condition is not classified elsewhere in ICD-10.

Resources & References

Resources for coding F99 include the latest version of ICD-10, clinical coding tools, and professional coding organizations.

Official Guidelines:

  • ICD-10
  • American Health Information Management Association (AHIMA)
  • American Academy of Professional Coders (AAPC)

Clinical References:

  • American Psychiatric Association (APA)
  • National Institute of Mental Health (NIMH)

Educational Materials:

  • ICD-10 coding training courses
  • Medical coding webinars
  • Coding clinics

Frequently Asked Questions

When should I use F99?

F99 should be used when a patient presents with symptoms of a mental disorder, but the specific condition is not documented or cannot be classified elsewhere in ICD-10.