R40.21 – Coma scale, eyes open

ICD-10-CM 2027 diagnosis code · Symptoms and signs involving cognition, perception, emotional state and behavior

Non-billable header

ICD-10-CM code R40.21

Code: R40.21 (claims format: R4021)
Description: Coma scale, eyes open
Billable: No – use a more specific code below
Valid for: Dates of service October 1, 2026 – September 30, 2027 (FY2027)
Chapter: 18. Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R99)
Block: R40-R46 Symptoms and signs involving cognition, perception, emotional state and behavior
Parent codes: R40 › R40.2

Billable codes under R40.21

R40.21 is a header code and cannot be used on claims. Choose the most specific code:

R40.211 – Coma scale, eyes open, neverHeader (more codes below)
R40.212 – Coma scale, eyes open, to painHeader (more codes below)
R40.213 – Coma scale, eyes open, to soundHeader (more codes below)
R40.214 – Coma scale, eyes open, spontaneousHeader (more codes below)

7th character values

Codes in this category need a 7th character to describe the encounter or episode of care (use placeholder X for empty positions).

Character	Meaning
`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

Notes for R40.21

7th character note:

The following appropriate 7th character is to be added to subcategory R40.21-:

Notes inherited from parent codes

Instructional notes at a category or block level apply to every code below it.

R40 – Somnolence, stupor and coma

Excludes1 (not coded here):

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)

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

Block R40-R46

Excludes2 (not included here):

symptoms and signs constituting part of a pattern of mental disorder (F01-F99)

Related codes in R40.2

R40.20 – Unspecified comaBillable
R40.22 – Coma scale, best verbal responseHeader
R40.23 – Coma scale, best motor responseHeader
R40.24 – Glasgow coma scale, total scoreHeader
R40.2A – Nontraumatic coma due to underlying conditionBillable

Frequently asked questions

What is ICD-10 code R40.21?

R40.21 is the ICD-10-CM code for coma scale, eyes open, in the block R40-R46 (Symptoms and signs involving cognition, perception, emotional state and behavior).

Is R40.21 a billable code?

No. R40.21 is a header code with more specific child codes; report one of the billable codes listed above.

What category does R40.21 belong to?

It belongs to category R40 – Somnolence, stupor and coma.

Source: CDC/NCHS ICD-10-CM FY2027 code files, tabular list and index. Reference only – code assignment must follow the official ICD-10-CM guidelines and documentation in the medical record.