ICD-10 Code F31.9 – Bipolar disorder, unspecified (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code F31.9 – Bipolar disorder, unspecified
What it is
F31.9 identifies bipolar disorder when the record confirms a bipolar diagnosis but does not specify the current episode or subtype. Use it for documented bipolar illness without enough detail for a more specific code.
Clinical signs
Clinical features vary; refer to documentation. Bipolar disorder may include episodes of elevated or irritable mood, increased energy, decreased need for sleep, and periods of depression.
When to use this code
Use this code when the provider documents bipolar disorder and does not state whether the episode is manic, depressed, mixed, or in remission. It also fits when the chart lacks enough detail to assign a more specific F31 code. Check documentation for episode type and current status.
Do not use for
Do not use F31.9 if the record clearly identifies a specific bipolar episode or remission status. Do not substitute it for mood disorders, psychotic disorders, or depression without a documented bipolar diagnosis.
Coding tip
Query for the current episode and remission status before defaulting to F31.9.