2026 ICD-10-CM Diagnosis Code S40.861SInsect bite (nonvenomous) of right upper arm, sequela

ICD-10-CM Codes›S00–T88›S40-S49›S40

ICD-10-CM S40.861S
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

S40.861S is a billable ICD-10-CM diagnosis code for insect bite (nonvenomous) of right upper arm, sequela. The 7th character S marks it as a sequela code, which reports a problem that remains after the original condition has resolved. 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. The code is exempt from POA reporting. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Injury, sequela.

Code Identity

ICD-10-CM Code
S40.861S
Billable Status
Yes — Valid for Submission
Code Describes
Insect bite (nonvenomous) of right upper arm, sequela
Short Description
Insect bite (nonvenomous) of right upper arm, sequela
Same as the full description in the CMS dataset.
Parent Code
S40.861
Insect bite (nonvenomous) of right upper arm

Code Classification

ChapterS00–T88Injury, poisoning and certain other consequences of external causes
SectionS40-S49Injuries to the shoulder and upper arm
CategoryS40Superficial injury of shoulder and upper arm
This CodeS40.861SInsect bite (nonvenomous) of right upper arm, sequela

Present on Admission (POA)Billing

S40.861S 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.

  • Animal bite of axilla
  • Animal bite of upper arm
  • Bite in axilla
  • Infected nonvenomous insect bite of right axilla
  • Infected wound of right upper arm due to non venomous insect bite
  • Insect bite, nonvenomous, of axilla
  • Insect bite, nonvenomous, of upper arm
  • Nonvenomous insect bite of axilla with infection
  • Nonvenomous insect bite of upper arm with infection
  • Superficial injury of axilla with infection
  • Superficial injury of right upper arm
  • Wound of right axilla due to nonvenomous insect bite
  • Wound of right upper arm due to nonvenomous insect bite

Coding GuidelinesGuidance

The appropriate 7th character is to be added to each code from block Superficial injury of shoulder and upper arm (S40). 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 INJ073
Injury, sequela
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Insect Bites and Stings

Most insect bites are harmless, though they sometimes cause discomfort. Bee, wasp, and hornet stings and fire ant bites usually hurt. Mosquito and flea bites usually itch. Insects can also spread diseases. In the United States, some mosquitoes spread West Nile virus.

Read the full article at MedlinePlus

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

Convert S40.861S to ICD-9-CMHistory

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

ICD-9-CM
906.2 Late eff superficial inj
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 S40.861SOverview

Is S40.861S (Insect bite (nonvenomous) of right upper arm) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report insect bite (nonvenomous) of right upper arm, sequela on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What does the 7th character S in S40.861S mean?

The final character S makes this a sequela code: it reports a lingering problem that remains after the insect bite (nonvenomous) of right upper arm itself has resolved, not the original event.

What MS-DRG does S40.861S group to?

When insect bite (nonvenomous) of right upper arm, sequela is the principal diagnosis on an inpatient stay, it groups to MS-DRG 604, 605, with relative weights from 0.9160 to 1.4721 depending on complications. Higher weights mean higher Medicare reimbursement.

Is S40.861S 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 insect bite (nonvenomous) of right upper arm, sequela on inpatient claims.

What is the ICD-9 equivalent of S40.861S?

Under the General Equivalence Mappings, insect bite (nonvenomous) of right upper arm, sequela converts to ICD-9-CM 906.2 (late eff superficial inj). 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.