ICD-10 Code F31.3 – Bipolar disorder, current episode depressed, mild or moderate severity (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code F31.3 – Bipolar disorder, current episode depressed, mild or moderate severity
What it is
This code identifies bipolar disorder when the current episode is depressed and the depression is mild or moderate. Use it when documentation specifies bipolar disorder with a depressive episode, not mania or mixed features.
Clinical signs
Typical findings include low mood, reduced interest, fatigue, poor concentration, sleep change, and other depressive symptoms in a person with bipolar disorder. Clinical features vary; refer to documentation.
When to use this code
Use this code when the record clearly states bipolar disorder with the current episode depressed and the severity is mild or moderate. It also fits follow-up visits when the clinician continues to document that same episode and severity.
If the note does not specify severity, or if the episode is manic, mixed, or in remission, you should not choose this code. Check documentation for the exact current episode.
Do not use for
Do not use this code for bipolar disorder with mania, mixed episode, or remission. Do not use it when the depression is severe or the documentation does not support bipolar disorder.
Coding tip
Match the code to the documented current episode and severity; if either is missing, query the provider.