2026 ICD-10-CM Diagnosis Code S50.879AOther superficial bite of unspecified forearm, initial encounter

ICD-10-CM CodesS00–T88S50-S59S50

ICD-10-CM S50.879A
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

S50.879A is a billable ICD-10-CM diagnosis code for other superficial bite of unspecified forearm, 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
S50.879A
Billable Status
Yes — Valid for Submission
Code Describes
Other superficial bite of unspecified forearm, initial encounter
Short Description
Other superficial bite of unspecified forearm, init encntr
Parent Code
Other superficial bite of unspecified forearm

Code Classification

ChapterS00–T88Injury, poisoning and certain other consequences of external causes
SectionS50-S59Injuries to the elbow and forearm
CategoryS50Superficial injury of elbow and forearm
This CodeS50.879AOther superficial bite of unspecified forearm, initial encounter

Coding GuidelinesGuidance

The appropriate 7th character is to be added to each code from block Superficial injury of elbow and forearm (S50). 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

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Convert S50.879A to ICD-9-CMHistory

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

ICD-9-CM
913.8 Superf inj forearm NEC
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 S50.879AOverview

Is S50.879A (Other superficial bite of unspecified forearm) a billable code?

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

What does the 7th character A in S50.879A mean?

The final character A marks the initial encounter: use it while the patient is receiving active treatment for other superficial bite of unspecified forearm, such as an emergency visit or first evaluation.

What MS-DRG does S50.879A group to?

When other superficial bite of unspecified forearm, 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 S50.879A?

Under the General Equivalence Mappings, other superficial bite of unspecified forearm, initial encounter converts to ICD-9-CM 913.8 (superf inj forearm 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.