2027 ICD-10-CM Diagnosis Code S40.829DBlister (nonthermal) of unspecified upper arm, subsequent encounter

ICD-10-CM Codes›S00–T88›S40-S49›S40

ICD-10-CM S40.829D
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

S40.829D is a billable ICD-10-CM diagnosis code for blister (nonthermal) of unspecified upper arm, 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 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 949 through 950. The code is exempt from POA reporting. Coders also document this condition as blister of axilla with infection. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Superficial injury; contusion, subsequent encounter.

Code Identity

ICD-10-CM Code
S40.829D
Billable Status
Yes — Valid for Submission
Code Describes
Blister (nonthermal) of unspecified upper arm, subsequent encounter
Short Description
Blister (nonthermal) of unspecified upper arm, subs encntr
Parent Code
S40.829
Blister (nonthermal) of unspecified 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 CodeS40.829DBlister (nonthermal) of unspecified upper arm, subsequent encounter

Present on Admission (POA)Billing

S40.829D is exempt from POA reporting on inpatient claims to general acute care hospitals. Review the other POA exempt codes in Injuries to the shoulder and upper arm (S40-S49).

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Blister of axilla with infection
  • Blister of axilla without infection
  • Blister of upper arm with infection
  • Blister of upper arm without infection
  • Superficial injury of axilla with infection
  • Traumatic blister of axilla
  • Traumatic blister of axilla with infection
  • Traumatic blister of shoulder and upper arm, infected
  • Traumatic blister of upper arm
  • Traumatic blister of upper arm, infected

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 S40.829D: 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.

From Block S40-S49 Injuries to the shoulder and upper arm applies to 2,730 codes
  • 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.

From Block S40-S49 Injuries to the shoulder and upper arm applies to 2,730 codes
From Chapter 19 (S00-T88) Injury, poisoning and certain other consequences of external causes applies to 41,187 codes

Use Additional Code

Add a second code, after this one, to fully describe the condition.

From Chapter 19 (S00-T88) Injury, poisoning and certain other consequences of external causes applies to 41,187 codes
  • code to identify any retained foreign body, if applicable (Z18.-)

Notes

General instructions on how these codes are used.

From Chapter 19 (S00-T88) Injury, poisoning and certain other consequences of external causes applies to 41,187 codes
  • 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.

From S40 Superficial injury of shoulder and upper arm applies to 144 codes
  • The appropriate 7th character is to be added to each code from category S40
Values for category S40 Encounter: Initial, Subsequent, Sequela
  • Ainitial encounter
  • Dsubsequent encounter this code
  • 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.

CCSR INJ054
Superficial injury; contusion, subsequent encounter
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Blisters

Blisters are fluid-filled sacs on the outer layer of your skin. They form because of rubbing, heat, or diseases of the skin. They are most common on your hands and feet.

The full article covers:

  • What are blisters?
  • What causes blisters?
  • What are the treatments for blisters?
  • Can blisters be prevented?

Read the full article at MedlinePlus

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

Convert S40.829D 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 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About S40.829DOverview

What is the ICD-10 code for blister (nonthermal) of unspecified upper arm, subsequent encounter?

The ICD-10-CM code for blister (nonthermal) of unspecified upper arm, subsequent encounter is S40.829D (sometimes written as S40829D). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is S40.829D (Blister (nonthermal) of unspecified upper arm) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report blister (nonthermal) of unspecified upper arm, subsequent encounter on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What does the 7th character D in S40.829D mean?

The final character D marks a subsequent encounter: use it for routine care while the blister (nonthermal) of unspecified upper arm is healing, after active treatment has ended.

What MS-DRG does S40.829D group to?

When blister (nonthermal) of unspecified upper arm, subsequent encounter is the principal diagnosis on an inpatient stay, it groups to MS-DRG 950, 949, with relative weights from 0.7661 to 1.1231 depending on complications. Higher weights mean higher Medicare reimbursement.

Is S40.829D 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 blister (nonthermal) of unspecified upper arm, subsequent encounter on inpatient claims. The code appears in the Injuries to the shoulder and upper arm (S40-S49) range of the CMS exempt list.