2026 ICD-10-CM Diagnosis Code S00.451ASuperficial foreign body of right ear, initial encounter

ICD-10-CM CodesS00–T88S00-S09S00

ICD-10-CM S00.451A
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

S00.451A is a billable ICD-10-CM diagnosis code for superficial foreign body of right ear, 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 604 through 605, 963 through 965. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Superficial injury; contusion, initial encounter.

Code Identity

ICD-10-CM Code
S00.451A
Billable Status
Yes — Valid for Submission
Code Describes
Superficial foreign body of right ear, initial encounter
Short Description
Superficial foreign body of right ear, initial encounter
Same as the full description in the CMS dataset.
Parent Code
Superficial foreign body of right ear

Code Classification

ChapterS00–T88Injury, poisoning and certain other consequences of external causes
SectionS00-S09Injuries to the head
CategoryS00Superficial injury of head
This CodeS00.451ASuperficial foreign body of right ear, initial encounter

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Foreign body in right ear
  • Foreign body in right external ear
  • Foreign body in skin of ear
  • Foreign body in skin of ear with infection
  • Foreign body in skin of right ear
  • Foreign body in skin of right ear with infection
  • Superficial injury of ear with infection
  • Superficial injury of right ear

Coding GuidelinesGuidance

The appropriate 7th character is to be added to each code from block Superficial injury of head (S00). 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 INJ017
Superficial injury; contusion, initial encounter
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Ear Disorders

Your ear has three main parts: outer, middle and inner. You use all of them in hearing. Sound waves come in through your outer ear. They reach your middle ear, where they make your eardrum vibrate. The vibrations are transmitted through three tiny bones, called ossicles, in your middle ear.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert S00.451A to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
910.6 Foreign body head
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About S00.451AOverview

Is S00.451A (Superficial foreign body of right ear) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report superficial foreign body of right ear, initial encounter on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What does the 7th character A in S00.451A mean?

The final character A marks the initial encounter: use it while the patient is receiving active treatment for superficial foreign body of right ear, such as an emergency visit or first evaluation.

What MS-DRG does S00.451A group to?

When superficial foreign body of right ear, initial encounter is the principal diagnosis on an inpatient stay, it groups to MS-DRG 604, 605, 963, 964, 965, with relative weights from 0.9160 to 2.7338 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of S00.451A?

Under the General Equivalence Mappings, superficial foreign body of right ear, initial encounter converts to ICD-9-CM 910.6 (foreign body head). The mapping is approximate, so confirm the match fits the documentation.

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.