2026 ICD-10-CM Diagnosis Code S00.409AUnspecified superficial injury of unspecified ear, initial encounter
S00.409A is a billable ICD-10-CM diagnosis code for unspecified superficial injury of unspecified 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. Coders also document this condition as superficial injury of ear region. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Superficial injury; contusion, initial encounter.
Code Identity
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Superficial injury of ear region
- Superficial injury of ear with infection
- Superficial injury of ear without infection
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.
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.
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Convert S00.409A to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About S00.409AOverview
Is S00.409A (Unspecified superficial injury of unspecified ear) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report unspecified superficial injury of unspecified ear, initial encounter on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What does the 7th character A in S00.409A mean?
The final character A marks the initial encounter: use it while the patient is receiving active treatment for unspecified superficial injury of unspecified ear, such as an emergency visit or first evaluation.
What MS-DRG does S00.409A group to?
When unspecified superficial injury of unspecified 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 S00.409A?
Under the General Equivalence Mappings, unspecified superficial injury of unspecified ear, initial encounter converts to ICD-9-CM 910.8 (superfic inj head NEC). 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.
