R40.0

ICD-10Billable

Somnolence

Official ICD-10-CM descriptor (FY2026)

Somnolence

R40.0 is valid for submission on a claim — CMS flags it as a billable, specific code.

Inclusion terms

Drowsiness

Excludes1

Not coded here. An Excludes1 code should never be reported at the same time as the code above it.

coma (R40.2-)

Related codes in R40

Where this code sits

Chapter: 18. Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R99)
Block: Symptoms and signs involving cognition, perception, emotional state and behavior (R40-R46)
Parent code: R40

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Source

ICD-10-CM FY2026. Centers for Medicare & Medicaid Services (CMS) / National Center for Health Statistics (NCHS), “2026 ICD-10-CM Code Descriptions in Tabular Order” (icd10cm_order_2026.txt). Download the original file from cms.gov. Public domain (US Government work). Descriptors, billable flags and instructional notes on this page are reproduced from that file without modification. Krasyn adds no clinical guidance.