2026 ICD-10-CM Diagnosis Code S06.A1XATraumatic brain compression with herniation, initial encounter

ICD-10-CM Codes›S00–T88›S00-S09›S06

ICD-10-CM S06.A1XA
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

S06.A1XA is a billable ICD-10-CM diagnosis code for traumatic brain compression with herniation, initial encounter. The 7th character A marks it as an initial encounter code, used while the patient is receiving active treatment. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 963 through 965. The code is not accepted as a principal diagnosis by the Medicare Code Editor. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Traumatic brain injury (TBI); concussion, initial encounter.

Code Identity

ICD-10-CM Code
S06.A1XA
Billable Status
Yes — Valid for Submission
Code Describes
Traumatic brain compression with herniation, initial encounter
Short Description
Traumatic brain compression with herniation, init
Parent Code
S06.A1
Traumatic brain compression with herniation

Code Classification

ChapterS00–T88Injury, poisoning and certain other consequences of external causes
SectionS00-S09Injuries to the head
CategoryS06Intracranial injury
This CodeS06.A1XATraumatic brain compression with herniation, initial encounter

Code EditsBilling

Medicare Code Editor checks that affect claim validity for S06.A1XA.

Unacceptable principal diagnosis
There are selected codes that describe a circumstance which influences an individual's health status but not a current illness or injury, or codes that are not specific manifestations but may be due to an underlying cause. These codes are considered unacceptable as a principal diagnosis.

Coding GuidelinesGuidance

The appropriate 7th character is to be added to each code from block Intracranial injury (S06). Use the following options for the applicable episode of care:

  • A - initial encounter
  • D - subsequent encounter
  • S - sequela

Source: ICD-10-CM Official Guidelines for Coding and Reporting, FY 2026, published by CMS and the National Center for Health Statistics.

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR INJ008
Traumatic brain injury (TBI); concussion, initial encounter
Default principal diagnosis: inpatient Yes · outpatient Yes

Code History & ChangesHistory

Replacement S06.A1XA replaces the following previously assigned code(s):

  • S06.890A - Intcran inj w/o loss of consciousness, init encntr
  • S06.899A - Intcran inj w loss of consciousness of unsp duration, init
FY 2022AddedAdded to the ICD-10-CM code setEffective October 1, 2021.
FY 2023–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About S06.A1XAOverview

Is S06.A1XA (Traumatic brain compression with herniation) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report traumatic brain compression with herniation, initial encounter on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What does the 7th character A in S06.A1XA mean?

The final character A marks the initial encounter: use it while the patient is receiving active treatment for traumatic brain compression with herniation, such as an emergency visit or first evaluation.

What MS-DRG does S06.A1XA group to?

On inpatient claims, traumatic brain compression with herniation, initial encounter maps to MS-DRG 963, 964, 965, with relative weights from 0.9405 to 2.7338 depending on complications. Higher weights mean higher Medicare reimbursement.

Can S06.A1XA be a principal diagnosis?

No. The Medicare Code Editor rejects this code as a principal diagnosis because traumatic brain compression with herniation, initial encounter describes a circumstance that influences health status rather than a current illness. Report it as a secondary diagnosis.

Footnotes

[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.