ICD-10 Code F31.8 – Other bipolar disorders (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code F31.8 – Other bipolar disorders
What it is
F31.8 identifies bipolar disorder presentations that do not fit a more specific bipolar subtype. Use it when the record supports bipolar illness, but the documentation does not match another coded category.
Clinical signs
Clinical features vary; refer to documentation. You may see episodes of elevated or irritable mood, increased activity, and periods of depression, with impairment in functioning.
When to use this code
Use this code when the clinician documents bipolar disorder and specifies “other” or a presentation not otherwise classified in the available record. It is appropriate when the chart lacks enough detail for a more specific bipolar code. Check documentation for episode type, current state, and any specifiers.
Do not use for
Do not use F31.8 when the record clearly supports a more specific bipolar diagnosis, such as bipolar I or bipolar II. Also avoid it if the documentation does not confirm bipolar disorder at all.
Coding tip
If the note is vague, query for the exact bipolar subtype before defaulting to F31.8.