2026 ICD-10-CM Diagnosis Code S21.151DOpen bite of right front wall of thorax without penetration into thoracic cavity, subsequent encounter

ICD-10-CM Codes›S00–T88›S20-S29›S21

ICD-10-CM S21.151D
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

S21.151D is a billable ICD-10-CM diagnosis code for open bite of right front wall of thorax without penetration into thoracic cavity, subsequent encounter. The 7th character D marks it as a subsequent encounter code, used during routine care in the healing or recovery phase. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 949 through 950. The code is exempt from POA reporting. Coders also document this condition as dog bite of chest. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Open wounds of trunk, subsequent encounter.

Code Identity

ICD-10-CM Code
S21.151D
Billable Status
Yes — Valid for Submission
Code Describes
Open bite of right front wall of thorax without penetration into thoracic cavity, subsequent encounter
Short Description
Open bite of r frnt wl of thorax w/o penet thor cavity, subs
Parent Code
S21.151
Open bite of right front wall of thorax without penetration into thoracic cavity

Code Classification

ChapterS00–T88Injury, poisoning and certain other consequences of external causes
SectionS20-S29Injuries to the thorax
CategoryS21Open wound of thorax
This CodeS21.151DOpen bite of right front wall of thorax without penetration into thoracic cavity, subsequent encounter

Present on Admission (POA)Billing

S21.151D is exempt from POA reporting on inpatient claims to general acute care hospitals. Review other POA exempt codes.

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Dog bite of chest
  • Human bite of chest
  • Open bite of thorax
  • Open wound of right chest wall due to dog bite
  • Open wound of right chest wall due to human bite

Coding GuidelinesGuidance

The appropriate 7th character is to be added to each code from block Open wound of thorax (S21). 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 INJ050
Open wounds of trunk, subsequent encounter
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Animal Bites

Wild animals usually avoid people. They might attack, however, if they feel threatened, are sick, or are protecting their young or territory. Attacks by pets are more common. Animal bites rarely are life-threatening, but if they become infected, you can develop serious medical problems.

Read the full article at MedlinePlus

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

Convert S21.151D to ICD-9-CMHistory

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

ICD-9-CM
V58.89 Other specfied aftercare
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 S21.151DOverview

Is S21.151D a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report open bite of right front wall of thorax without penetration into thoracic cavity, subsequent encounter on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What does the 7th character D in S21.151D mean?

The final character D marks a subsequent encounter: use it for routine care while the open bite of right front wall of thorax without penetration into thoracic cavity is healing, after active treatment has ended.

What MS-DRG does S21.151D group to?

When open bite of right front wall of thorax without penetration into thoracic cavity, subsequent encounter is the principal diagnosis on an inpatient stay, it groups to MS-DRG 949, 950, with relative weights from 0.6277 to 1.1897 depending on complications. Higher weights mean higher Medicare reimbursement.

Is S21.151D exempt from POA reporting?

Yes. CMS lists this code among those exempt from present on admission reporting, so hospitals do not assign a POA indicator for open bite of right front wall of thorax without penetration into thoracic cavity, subsequent encounter on inpatient claims.

What is the ICD-9 equivalent of S21.151D?

Under the General Equivalence Mappings, open bite of right front wall of thorax without penetration into thoracic cavity, subsequent encounter converts to ICD-9-CM V58.89 (other specfied aftercare). 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.