2027 ICD-10-CM Diagnosis Code S40.861AInsect bite (nonvenomous) of right upper arm, initial encounter
S40.861A is a billable ICD-10-CM diagnosis code for insect bite (nonvenomous) of right upper arm, 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 606 through 607, 963 through 965. 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.
- Animal bite of axilla
- Bite in axilla
- Bite wound of right shoulder
- Bite wound of right upper arm
- 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 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 S40.861A: its own notes plus those printed at S40, block S40-S49, and Chapter 19. A note printed at a category, block or chapter applies to every code under it.
Includes
Further defines, or gives examples of, the content of the category.
- injuries of axilla
- injuries of scapular region
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.-)
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 S40
- Ainitial encounter this code
- Dsubsequent encounter
- Ssequela
Source: CMS ICD-10-CM Tabular List. How to read instructional notes.
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
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 S40.861A to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About S40.861AOverview
What is the ICD-10 code for insect bite (nonvenomous) of right upper arm, initial encounter?
The ICD-10-CM code for insect bite (nonvenomous) of right upper arm, initial encounter is S40.861A (sometimes written as S40861A). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
Is S40.861A (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, initial encounter on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What does the 7th character A in S40.861A mean?
The final character A marks the initial encounter: use it while the patient is receiving active treatment for insect bite (nonvenomous) of right upper arm, such as an emergency visit or first evaluation.
What MS-DRG does S40.861A group to?
When insect bite (nonvenomous) of right upper arm, initial encounter is the principal diagnosis on an inpatient stay, it groups to MS-DRG 964, 965, 607, 963, 606, with relative weights from 0.8772 to 2.6361 depending on complications. Higher weights mean higher Medicare reimbursement.
What is the ICD-9 equivalent of S40.861A?
Under the General Equivalence Mappings, insect bite (nonvenomous) of right upper arm, initial encounter converts to ICD-9-CM 912.4 (insect bite shoulder/arm). The mapping is approximate, so confirm the match fits the documentation.
