Billable / Specific Code
ICD-10-CM F99 is the diagnosis code for Mental disorder, not otherwise specified. This code falls under the section "Unspecified mental disorder" within Chapter 5 — Mental, Behavioral and Neurodevelopmental disorders (F01-F99). It is a billable/specific ICD-10-CM code that can be used to indicate a diagnosis for reimbursement purposes. Medical coders and healthcare providers use this code to document and classify diagnoses in electronic health records, insurance claims, and clinical databases.
The following conditions should never be coded at the same time as F99. They are mutually exclusive:
Understanding where F99 sits in the ICD-10-CM classification helps ensure proper coding:
Yes, F99 is a billable/specific ICD-10-CM code that can be used to indicate a diagnosis for reimbursement purposes.
F99 is the ICD-10-CM diagnosis code for "Mental disorder, not otherwise specified". It is used by healthcare providers to classify and document this condition in medical records and insurance claims.
F99 is located in Section F99 — "Unspecified mental disorder" within Chapter 5 of the ICD-10-CM Tabular List.
Use F99 when the patients documented diagnosis matches "Mental disorder, not otherwise specified" and the clinical documentation supports this level of specificity. Always verify with the latest ICD-10-CM guidelines and payer requirements.
The ICD-10-CM code for Mental disorder, not otherwise specified is F99.
Yes, F99 can be used as a primary diagnosis code since it is billable and specific.
F99 is in Chapter 5 of the ICD-10-CM Tabular List.
Type 1 Excludes for F99 include: unspecified mental disorder due to known physiological condition (F09).
Yes, F99 is a valid ICD-10-CM code for the 2026 fiscal year, subject to official CMS updates.