2026 ICD-10-CM Diagnosis Code S90.551ASuperficial foreign body, right ankle, initial encounter
S90.551A is a billable ICD-10-CM diagnosis code for superficial foreign body, right ankle, 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 foreign body in skin of ankle. 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.
- Foreign body in skin of ankle
- Foreign body in skin of right ankle
- Superficial injury of right ankle
Coding GuidelinesGuidance
The appropriate 7th character is to be added to each code from block Superficial injury of ankle, foot and toes (S90). 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
Foreign Bodies
If you've ever gotten a splinter or had sand in your eye, you've had experience with a foreign body. A foreign body is something that is stuck inside you but isn't supposed to be there. You may inhale or swallow a foreign body, or you may get one from an injury to almost any part of your body.
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert S90.551A to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About S90.551AOverview
Is S90.551A (Superficial foreign body, right ankle) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report superficial foreign body, right ankle, initial encounter on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What does the 7th character A in S90.551A mean?
The final character A marks the initial encounter: use it while the patient is receiving active treatment for superficial foreign body, right ankle, such as an emergency visit or first evaluation.
What MS-DRG does S90.551A group to?
When superficial foreign body, right ankle, 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 S90.551A?
Under the General Equivalence Mappings, superficial foreign body, right ankle, initial encounter converts to ICD-9-CM 916.6 (foreign body hip/leg). 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.
