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ICD-10 Guide
ICD-10 CodesF51.1

F51.1

Billable

Hypersomnia not due to a substance or known physiological condition

BILLABLE STATUSYes
IMPLEMENTATION DATEOctober 1, 2015
LAST UPDATED09/05/2025

Code Description

ICD-10 F51.1 is a billable code used to indicate a diagnosis of hypersomnia not due to a substance or known physiological condition.

Key Diagnostic Point:

Hypersomnia not due to a substance or known physiological condition is characterized by excessive daytime sleepiness that is not attributable to any substance use or identifiable medical condition. Patients may experience prolonged sleep episodes, difficulty waking up, and a persistent need for sleep that interferes with daily activities. This condition can significantly impact quality of life, leading to difficulties in occupational and social functioning. It is essential to differentiate hypersomnia from other sleep disorders, such as narcolepsy or sleep apnea, as well as from conditions like depression or anxiety that may also contribute to excessive sleepiness. Diagnosis typically involves a thorough clinical evaluation, including sleep history, sleep diaries, and possibly polysomnography to rule out other sleep disorders. Treatment may include lifestyle modifications, cognitive behavioral therapy, and pharmacological interventions aimed at managing symptoms and improving wakefulness.

Code Complexity Analysis

Complexity Rating: Medium

Medium Complexity

Complexity Factors

  • Differentiating from other sleep disorders like narcolepsy and sleep apnea.
  • Need for comprehensive patient history to rule out other causes.
  • Potential overlap with psychiatric conditions such as depression.
  • Variability in symptoms and patient reporting.

Audit Risk Factors

  • Inadequate documentation of sleep history and symptoms.
  • Failure to rule out other sleep disorders.
  • Lack of follow-up documentation on treatment efficacy.
  • Misclassification of hypersomnia as a primary diagnosis without supporting evidence.

Specialty Focus

Medical Specialties

Sleep Medicine

Documentation Requirements

Detailed sleep history, sleep study results, and treatment plans.

Common Clinical Scenarios

Patients presenting with excessive daytime sleepiness, difficulty waking, and disrupted sleep patterns.

Billing Considerations

Consideration of comorbid conditions and the impact of medications on sleep.

Psychiatry

Documentation Requirements

Comprehensive mental health evaluation, including mood assessments and sleep patterns.

Common Clinical Scenarios

Patients with hypersomnia presenting with depressive symptoms or anxiety disorders.

Billing Considerations

Differentiating between hypersomnia as a primary condition versus secondary to psychiatric disorders.

Coding Guidelines

Inclusion Criteria

Use F51.1 When
  • According to ICD
  • 10 guidelines, F51
  • 1 should be used when hypersomnia is confirmed to be not due to substance use or a known physiological condition

Exclusion Criteria

Do NOT use F51.1 When
  • Documentation must support the diagnosis, including the exclusion of other potential causes

Related ICD-10 Codes

Related CPT Codes

95810CPT Code

Polysomnography, sleep study

Clinical Scenario

Used to diagnose sleep disorders including hypersomnia.

Documentation Requirements

Document the indication for the sleep study and results.

Specialty Considerations

Sleep specialists should ensure comprehensive reporting of findings.

ICD-10 Impact

Diagnostic & Documentation Impact

Enhanced Specificity

ICD-10 Improvements

The transition to ICD-10 has allowed for more specific coding of sleep disorders, including hypersomnia. This specificity aids in better understanding and management of the condition, leading to improved patient care.

ICD-9 vs ICD-10

The transition to ICD-10 has allowed for more specific coding of sleep disorders, including hypersomnia. This specificity aids in better understanding and management of the condition, leading to improved patient care.

Reimbursement & Billing Impact

reimbursement.

Resources

Clinical References

  • •
    American Academy of Sleep Medicine

Coding & Billing References

  • •
    American Academy of Sleep Medicine

Frequently Asked Questions

What are the common symptoms of hypersomnia?

Common symptoms include excessive daytime sleepiness, prolonged nighttime sleep, difficulty waking up, and a persistent need for naps during the day.

How is hypersomnia diagnosed?

Diagnosis typically involves a thorough clinical evaluation, including sleep history, sleep diaries, and possibly polysomnography to rule out other sleep disorders.