ICD-10-CM code · FY2027
F51.1 Hypersomnia not due to a substance or known physiological condition
Header codeNot billable: use one of the 4 billable codes below
About F51.1
- Code
- F51.1
- Billable
- No, header
- Short description
- Hypersomnia not due to a substance or known physiol cond
- Category
- F51 Sleep disorders not due to a substance or known physiological condition
- Block
- F50-F59 Behavioral syndromes associated with physiological disturbances and physical factors
- Chapter
- 5 Mental, Behavioral and Neurodevelopmental disorders
- Code set
- FY2027, October 1, 2026 to September 30, 2027
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Coding notes for F51.1
Excludes2 Not part of this condition, but a patient can have both: report both codes when both apply.
- alcohol related hypersomnia (F10.182, F10.282, F10.982)
- drug-related hypersomnia (F11.182, F11.282, F11.982, F13.182, F13.282, F13.982, F14.182, F14.282, F14.982, F15.182, F15.282, F15.982, F19.182, F19.282, F19.982)
- hypersomnia NOS (G47.10)
- hypersomnia due to known physiological condition (G47.10)
- idiopathic hypersomnia (G47.11, G47.12)
- narcolepsy (G47.4-)
Also applies, from F51 Sleep disorders not due to a substance or known physiological condition
Excludes2 Not part of this condition, but a patient can have both: report both codes when both apply.
- organic sleep disorders (G47.-)
Chapter 5 notes (apply to every code in it)
Includes Conditions this code covers.
- disorders of psychological development
Codes under F51.1 4
Related codes in F51
- F51.0 Insomnia not due to a substance or known physiological conditionHeader
- F51.3 Sleepwalking [somnambulism]Billable
- F51.4 Sleep terrors [night terrors]Billable
- F51.5 Nightmare disorderBillable
- F51.8 Other sleep disorders not due to a substance or known physiological conditionBillable
- F51.9 Sleep disorder not due to a substance or known physiological condition, unspecifiedBillable
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See 2MM+ plansICD-10-CM FY2027 code set, as published by the CDC National Center for Health Statistics (NCHS) and CMS, effective October 1, 2026 to September 30, 2027. Codes, titles and notes are shown as published. Check payer rules and the official guidelines before billing. This page is not medical advice.
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