Oth hypersomnia not due to a substance or known physiol cond

This code represents a primary sleep disorder characterized by excessive daytime sleepiness or prolonged nighttime sleep that is not attributable to drug use, medical conditions, or other sleep disorders like narcolepsy or sleep apnea. Patients experience significant difficulty staying awake during the day, often despite adequate sleep duration.

Use this code when documentation clearly indicates a diagnosis of hypersomnia where a thorough medical workup has ruled out secondary causes such as substance use, neurological disorders, or other sleep-related breathing disorders. This diagnosis is typically made after polysomnography and multiple sleep latency tests (MSLT) confirm excessive sleepiness and exclude other primary sleep disorders.

• Ensure documentation explicitly states "other hypersomnia" and rules out substance-induced or physiologically-induced causes.
• Do not use this code if narcolepsy (G47.41-) or sleep apnea (G47.3-) is the primary diagnosis for excessive sleepiness.
• Consider sequencing this code as the primary diagnosis when it is the main reason for the encounter, especially for sleep disorder evaluations and management.