U.S. ICD-10-CM · FY 2027

F51.1 ICD-10-CM Code: Hypersomnia not due to a substance or known physiological condition

A clear reference for the official code description, hierarchy, and related coding information from the FY 2027 U.S. release.

Code definition

Official description

F51.1

Hypersomnia not due to a substance or known physiological condition

ICD-10-CM diagnosis code · United States clinical modification

Classification

Where F51.1 sits

  1. 1

    Chapter 5

    Mental, Behavioral and Neurodevelopmental disorders (F01-F99)

  2. 2

    Section

    Behavioral syndromes associated with physiological disturbances and physical factors (F50-F59)

  3. 3

    Category F51

    Sleep disorders not due to a substance or known physiological condition

  4. 4

    Code F51.1

    Hypersomnia not due to a substance or known physiological condition

More specific choices

Codes under F51.1

F51.1 is a non-billable category. Choose the child code that best matches the documented diagnosis.

Documentation details

Notes for this code

Inclusion terms

No inclusion terms are listed for F51.1.

Code first

No “code first” instruction is listed for F51.1.

Use additional code

No “use additional code” instruction is listed for F51.1.

Excludes1

Conditions that should not be reported together with this code.

No Excludes1 note is listed for F51.1.

Excludes2

Conditions not included here that may be reported separately when 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-)

Transparency

Source and release

Data release

U.S. ICD-10-CM · FY 2027

Effective date

Oct 1, 2026

This reference is generated from Vero’s ICD-10-CM description, hierarchy, and code-note dataset. The visible content and structured data share that source.

Review the CDC/NCHS ICD-10-CM source

Code-specific guidance

Frequently asked questions

What does ICD-10-CM code F51.1 mean?

F51.1 is the FY 2027 U.S. ICD-10-CM code for “Hypersomnia not due to a substance or known physiological condition.”

Is F51.1 a billable or specific ICD-10-CM code?

No. F51.1 has more specific child codes in the FY 2027 reference data. Select the code that matches the documentation and confirm the active code set and payer requirements.

Where is F51.1 located in ICD-10-CM?

F51.1 is listed in Chapter 5, Mental, Behavioral and Neurodevelopmental disorders (F01-F99), within Behavioral syndromes associated with physiological disturbances and physical factors (F50-F59) (F50–F59), under category F51, Sleep disorders not due to a substance or known physiological condition.

What coding notes are listed for F51.1?

No inclusion terms are listed for F51.1 in this reference record. No code-first instruction is listed. No Excludes1 note is listed. Excludes2 notes: 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-).

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