2027 ICD-10-CM Diagnosis Code S86.321ALaceration of muscle(s) and tendon(s) of peroneal muscle group at lower leg level, right leg, initial encounter
ICD-10-CM Codes›S00–T88›S80-S89›S86
- Billable — Valid for Submission
- CC — Complication or Comorbidity
- 7th Character A — Initial Encounter
- Not Chronic
S86.321A is a billable ICD-10-CM diagnosis code for laceration of muscle(s) and tendon(s) of peroneal muscle group at lower leg level, right leg, 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 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 564 through 566, 963 through 965. As a secondary diagnosis, it counts as a complication or comorbidity (CC) and moves an inpatient stay to a higher severity level within its MS-DRG family. It does not count, however, when the principal diagnosis is one of 58 closely related codes. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Open wounds to limbs, initial encounter.
Code Identity
Code Classification
Coding GuidelinesGuidance
The appropriate 7th character is to be added to each code from block Injury of muscle, fascia and tendon at lower leg level (S86). 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 2027, published by CMS and the National Center for Health Statistics.
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to S86.321A: its own notes plus those printed at S86, block S80-S89, and Chapter 19. A note printed at a category, block or chapter applies to every code under it.
Excludes2
Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.
Use Additional Code
Add a second code, after this one, to fully describe the condition.
- code to identify any retained foreign body, if applicable (Z18.-)
Code Also
A second code may be needed to fully describe the condition; the note gives no sequencing direction.
Notes
General instructions on how these codes are used.
- Use secondary code(s) from Chapter 20, External causes of morbidity, to indicate cause of injury. Codes within the T section that include the external cause do not require an additional external cause code
- The chapter uses the S-section for coding different types of injuries related to single body regions and the T-section to cover injuries to unspecified body regions as well as poisoning and certain other consequences of external causes.
7th Character
Every code in the category takes a 7th character from the listed values, with the placeholder X filling any empty positions before it.
- The appropriate 7th character is to be added to each code from category S86
- Ainitial encounter this code
- Dsubsequent encounter
- Ssequela
Source: CMS ICD-10-CM Tabular List. How to read instructional notes.
Referenced in Other NotesGuidance
Instructional notes printed at other codes that name S86.321A, its category, or a range that includes it.
Excludes2 2
These codes carry an Excludes2 note naming S86.321A: its condition is not part of those codes, and both may be reported when the patient has both.
- S76 Injury of muscle, fascia and tendon at hip and thigh levelinjury of muscle, fascia and tendon at lower leg level (S86) names S86, which includes this code
- S83 Dislocation and sprain of joints and ligaments of kneestrain of muscle, fascia and tendon of lower leg (S86.-) names S86.-, which includes this code
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Patient EducationClinical
Leg Injuries and Disorders
Your legs are made up of bones, blood vessels, muscles, and other connective tissue. They are important for motion and standing. Playing sports, running, falling, or having an accident can damage your legs. Common leg injuries include sprains and strains, joint dislocations, and fractures (broken bones).
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert S86.321A to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About S86.321AOverview
Is S86.321A a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report laceration of muscle(s) and tendon(s) of peroneal muscle group at lower leg level, right leg, initial encounter on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What does the 7th character A in S86.321A mean?
The final character A marks the initial encounter: use it while the patient is receiving active treatment for laceration of muscle(s) and tendon(s) of peroneal muscle group at lower leg level, right leg, such as an emergency visit or first evaluation.
What MS-DRG does S86.321A group to?
When laceration of muscle(s) and tendon(s) of peroneal muscle group at lower leg level, right leg, initial encounter is the principal diagnosis on an inpatient stay, it groups to MS-DRG 564, 964, 965, 566, 565, 963, with relative weights from 0.7374 to 2.6361 depending on complications. Higher weights mean higher Medicare reimbursement.
Is S86.321A a CC or MCC?
CMS lists S86.321A as a CC (complication or comorbidity) for FY 2027. Reported as a secondary diagnosis, it moves the inpatient stay to a higher-weighted DRG within its severity family. It does not count when the principal diagnosis is one of the 58 closely related codes in its exclusion list.
What is the ICD-9 equivalent of S86.321A?
Under the General Equivalence Mappings, laceration of muscle(s) and tendon(s) of peroneal muscle group at lower leg level, right leg, initial encounter converts to ICD-9-CM 891.2 (opn wnd knee/leg w tendn). The mapping is approximate, so confirm the match fits the documentation.
