F51.1 Hypersomnia not due to a substance or known physiological condition

Not billable (header)Chapter 5

Report one of the more specific codes below.

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Codes under this one

F51.11 Primary hypersomnia
F51.12 Insufficient sleep syndrome
F51.13 Hypersomnia due to other mental disorder
F51.19 Other hypersomnia not due to a substance or known physiological condition

Instructional notes

Chapter 5

Excludes2Not included here: the patient may have both; report both when both are present.

symptoms, signs and abnormal clinical laboratory findings, not elsewhere classified (R00-R99)

Includes

disorders of psychological development

F51

Excludes2Not included here: the patient may have both; report both when both are present.

organic sleep disorders (G47.-)

This code

Excludes2Not included here: the patient may have both; report both when both are present.

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-)

Chapter 5: Mental, Behavioral and Neurodevelopmental disorders · F50-F59 Behavioral syndromes associated with physiological disturbances and physical factors (F50-F59)

Source: ICD-10-CM FY 2027 code descriptions and tabular list (CMS and CDC National Center for Health Statistics), effective 2026-10-01 through 2027-09-30 · CMS ICD-10 files. HCC mapping: CMS-HCC V28, payment year 2027. As of 2026-11-04.

Coverage and payment depend on the claim details; confirm with the Medicare Administrative Contractor.