R40.2431 Glasgow coma scale score 3-8, in the field [EMT or ambulance]

Billable ICD-10-CM code, FY2026.

Built from R40.243 with 7th character 1 (in the field [EMT or ambulance]).

Applies from R40 Somnolence, stupor and coma

Excludes1 (never code together)

• neonatal coma (P91.5)
• somnolence, stupor and coma in diabetes (E08-E13)
• somnolence, stupor and coma in hepatic failure (K72.-)
• somnolence, stupor and coma in hypoglycemia (nondiabetic) (E15)

Applies from R40.2 Coma

Code first

• any associated:
• fracture of skull (S02.-)
• intracranial injury (S06.-)

Notes

• One code from each subcategory, R40.21-R40.23, is required to complete the coma scale

Applies from R40.24 Glasgow coma scale, total score

7th character note

• The following appropriate 7th character is to be added to subcategory R40.24-:

Notes

• Assign a code from subcategory R40.24, when only the total coma score is documented

7th character required

• 0 — unspecified time
• 1 — in the field [EMT or ambulance]
• 2 — at arrival to emergency department
• 3 — at hospital admission
• 4 — 24 hours or more after hospital admission

Risk adjustment (HCC)

• CMS-HCC V28: HCC 202 — Coma, Brain Compression/Anoxic Damage
• CMS-HCC V22: HCC 80 — Coma, Brain Compression/Anoxic Damage
• ESRD V24: HCC 80

Medicare Code Edits (MCE v43.1 (April 2026))

• Unacceptable principal diagnosis: These codes describe a circumstance which influences care but is not a current illness or injury, or capture only an underlying condition, and are unacceptable as principal diagnosis.

Code annotations containing back-references to R40.2431

Back-references to R40.24

• Type 1 Excludes: R40.2A Nontraumatic coma due to underlying condition ("coma scale, best motor response (R40.24.-)")

Back-references to R40.2

• Type 1 Excludes: R40.0 Somnolence ("coma (R40.2-)")
• Type 1 Excludes: R40.1 Stupor ("coma (R40.2-)")
• Type 1 Excludes: R55 Syncope and collapse ("unconsciousness NOS (R40.2-)")

Back-references to R40

• Type 1 Excludes: R41.82 Altered mental status, unspecified ("altered level of consciousness (R40.-)")
• Use Additional: T67.0 Heatstroke and sunstroke ("coma and stupor (R40.-)")

Diagnosis Index entries for R40.2431

• Glasgow coma scale › total score › 3-8

Nearby codes

• R40.2422 Glasgow coma scale score 9-12, at arrival to emergency department
• R40.2423 Glasgow coma scale score 9-12, at hospital admission
• R40.2424 Glasgow coma scale score 9-12, 24 hours or more after hospital admission
• R40.243 Glasgow coma scale score 3-8
• R40.2430 Glasgow coma scale score 3-8, unspecified time
• R40.2431 Glasgow coma scale score 3-8, in the field [EMT or ambulance] (this code)
• R40.2432 Glasgow coma scale score 3-8, at arrival to emergency department
• R40.2433 Glasgow coma scale score 3-8, at hospital admission
• R40.2434 Glasgow coma scale score 3-8, 24 hours or more after hospital admission
• R40.244 Other coma, without documented Glasgow coma scale score, or with partial score reported
• R40.2440 Other coma, without documented Glasgow coma scale score, or with partial score reported, unspecified time