At a glance
Which insomnia code do I assign?
G47.00 is the not-otherwise-specified code in the G47.0 subcategory, appropriate when documentation supports an insomnia diagnosis but does not differentiate the subtype. The subcategory is organized by etiology. The first question is always whether the record names a cause.
Tabular notes
Operational & financial impact
Why specificity matters beyond the chart: risk adjustment, DRG assignment and denial exposure all follow from which code is selected.
Documentation checklist to support G47.00
Chart elements that support code selection and reduce specificity-driven denials.
FAQ
Use G47.01 when the insomnia is directly caused by a documented medical condition. G47.01 carries a Code Also instruction. The underlying condition must be coded as well. G47.00 is reserved for records where the provider documents insomnia but does not specify its type or cause. Assigning G47.00 when the documentation actually names the cause is one of the most common errors with this code.
No. G47.00 does not map to any Hierarchical Condition Category in CMS-HCC v28, which is fully operative at 100% weight for Medicare Advantage payment year 2026. Sleep disorders are not risk-adjusting conditions under the current CMS model. The code contributes nothing to a patient's risk score.
Code the psychiatric condition first and add G47.00 as an additional code only if the insomnia is separately addressed at the encounter. The insomnia does not become the principal diagnosis simply because it is the symptom the patient reports most prominently.
No. In the outpatient setting, code G47.00 only when insomnia is a confirmed diagnosis and is addressed at the encounter. Sleep disturbance symptoms should not be coded to G47.00 where no insomnia diagnosis is documented. In the inpatient setting, standard UHDDS uncertain diagnosis rules apply at discharge.
F51.01, primary insomnia, sits in category F51, sleep disorders not due to a substance or known physiological condition. The Index sends primary, idiopathic and nonorganic insomnia to F51.01 and psychophysiologic insomnia to F51.04. F51.01 appears in the Excludes2 entries at the G47.0 subcategory level, which means it is a separate condition rather than a more specific form of G47.00.
No. Hypersomnia is classified to G47.10 through G47.19, a different code family from the G47.0 insomnia subcategory. They are distinct conditions.
Related codes
Codes in the same family as G47.00. Only codes with a published page render as links.
Sibling codes in the G47.0 family
- G47.00: Insomnia, unspecified.
- G47.01: Insomnia due to medical condition.
- G47.09: Other insomnia.
Additional codes to consider
Codes outside the G47.0 family considered alongside G47.00.
Companion: code alongside when documented
No Code Also or Use Additional instruction attaches to G47.00 itself. When the provider documents the insomnia as due to depression, an anxiety disorder or another mental disorder, the Index directs it to F51.05, Insomnia due to other mental disorder, rather than G47.00. F51.05 carries a Code also note for the associated mental disorder.
Consider instead
- G47.01: Insomnia due to medical condition. Use when a documented medical condition is the cause, with Code Also for that condition.
- G47.09: Other insomnia. Use for insomnia types not classifiable to G47.00 or G47.01.
- F51.01: Primary insomnia. Consider when the documentation states primary, idiopathic or nonorganic insomnia.
- F51.05: Insomnia due to other mental disorder. Use when the provider links the insomnia to depression, an anxiety disorder or another mental disorder.
- F51.09: Other insomnia not due to a substance or known physiological condition.
- F10.182: Alcohol abuse with alcohol-induced sleep disorder. Excluded from G47.0 and used when the insomnia is alcohol-related.
- G47.10: Hypersomnia, unspecified. A separate condition, not to be conflated with insomnia.
- G47.30: Sleep apnea, unspecified. Assign a code from G47.30 to G47.39 for sleep apnea. The Excludes2 note at G47.0 permits reporting it with G47.00 when insomnia is also documented.
- G47.2-: Circadian rhythm sleep disorders. Use when the documented problem is the timing of sleep.
Sources
All claims on this page derive from government and professional-standards sources.
- National Center for Health Statistics. (2026). International classification of diseases, tenth revision, clinical modification (ICD-10-CM) FY2027 files. https://www.cdc.gov/nchs/icd/icd-10-cm/files.html
- Centers for Medicare & Medicaid Services and National Center for Health Statistics. (2026). ICD-10-CM official guidelines for coding and reporting FY2027. https://ftp.cdc.gov/pub/Health_Statistics/NCHS/Publications/ICD10CM/2027/ICD-10-CM-October-1-2026-FY27-Guidelines.pdf
- Centers for Medicare & Medicaid Services. (2025). 2026 model software/ICD-10 mappings. https://www.cms.gov/medicare/payment/medicare-advantage-rates-statistics/risk-adjustment/2026-model-software-icd-10-mappings
- Centers for Medicare & Medicaid Services. (2026). MS-DRG classifications and software, version 44. https://www.cms.gov/medicare/payment/prospective-payment-systems/acute-inpatient-pps/ms-drg-classifications-and-software