ICD-10 Code G47.1 – Hypersomnia (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code G47.1 – Hypersomnia
What it is
G47.1 identifies hypersomnia, a sleep disorder marked by excessive daytime sleepiness or prolonged sleep episodes. Use it when the record supports abnormal sleepiness that is not better explained by a different documented condition.
Clinical signs
Typical documentation includes persistent sleepiness, difficulty staying awake during the day, or sleeping for unusually long periods. Clinical features vary; refer to documentation.
When to use this code
Use G47.1 when the provider documents hypersomnia as the diagnosis, including idiopathic or recurrent forms if no more specific code is assigned. It may also apply when the chart describes excessive sleepiness without another confirmed cause. Check documentation if the sleepiness is linked to another disorder.
Do not use for
Do not use G47.1 for ordinary fatigue, insomnia, or sleep deprivation without a diagnosis of hypersomnia. If another condition explains the daytime sleepiness, code that condition instead.
Coding tip
Confirm that the provider documents hypersomnia specifically, because “sleepy” or “tired” alone is not enough.