F51.1 vs G47.4
F51.1 (Hypersomnia not due to a substance or known physiological condition) compared with G47.4 (Narcolepsy and cataplexy), from the official CMS tabular data. Both may be reported when both conditions are documented (Excludes2).
Can these codes be reported together?
Yes, when both are documented. F51.1 carries an Excludes2 note covering G47.4: “narcolepsy (G47.4-)”
Excludes2 marks distinct conditions — both may be reported when both are documented.
Yes, when both are documented. F51.1 carries an Excludes2 note covering G47.4: “organic sleep disorders (G47.-)”
Excludes2 marks distinct conditions — both may be reported when both are documented.
Yes, when both are documented. G47.4 carries an Excludes2 note covering F51.1: “nonorganic sleep disorders (F51.-)”
Excludes2 marks distinct conditions — both may be reported when both are documented.
Side by side
| F51.1Hypersomnia not due to a substance or known physiological condition | G47.4Narcolepsy and cataplexy | |
|---|---|---|
| Billing status | Non-billable header | Non-billable header |
| Classification | F01-F99 — Mental, Behavioral and Neurodevelopmental Disorders (F01-F99) | G00-G99 — Diseases of the Nervous System (G00-G99) |
| Definition | Hypersomnia not due to a substance or known physiological condition is a non-billable ICD-10-CM category code (F51.1). | Narcolepsy and cataplexy is a non-billable ICD-10-CM category code (G47.4). |
Derived from the official CMS ICD-10-CM tabular data (FY2026). Not billing advice; verify sequencing rules for the encounter. All data sources