2027 ICD-10-CM Diagnosis Code T75.21XAPneumatic hammer syndrome, initial encounter

ICD-10-CM Codes›S00–T88›T66-T78›T75

ICD-10-CM T75.21XA
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

T75.21XA is a billable ICD-10-CM diagnosis code for pneumatic hammer syndrome, 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 922 through 923. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Effect of other external causes, initial encounter; External cause codes: intent of injury, accidental/unintentional; and External cause codes: natural/environment; initial encounter.

Code Identity

ICD-10-CM Code
T75.21XA
Billable Status
Yes — Valid for Submission
Code Describes
Pneumatic hammer syndrome, initial encounter
Short Description
Pneumatic hammer syndrome, initial encounter
Same as the full description in the CMS dataset.
Parent Code
T75.21
Pneumatic hammer syndrome

Code Classification

ChapterS00–T88Injury, poisoning and certain other consequences of external causes
SectionT66-T78Other and unspecified effects of external causes
CategoryT75Other and unspecified effects of other external causes
This CodeT75.21XAPneumatic hammer syndrome, initial encounter

Coding GuidelinesGuidance

The appropriate 7th character is to be added to each code from block Other and unspecified effects of other external causes (T75). 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 T75.21XA: its own notes plus those printed at T75, block T66-T78, and Chapter 19. A note printed at a category, block or chapter applies to every code under it.

Excludes1

Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.

From T75 Other and unspecified effects of other external causes applies to 48 codes
  • adverse effects NEC (T78.-)

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 T75 Other and unspecified effects of other external causes applies to 48 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.-)

Code Also

A second code may be needed to fully describe the condition; the note gives no sequencing direction.

From Block T66-T78 Other and unspecified effects of external causes applies to 456 codes
  • if applicable, place of occurrence, such as:
  • highway rest stop (Y92.523)
  • school (private) (public) (state) as the place of occurrence of the external cause (Y92.21-)
  • service areas as the place of occurrence of the external cause (Y92.52-)
  • single-family non-institutional (private) house as the place of occurrence of the external cause (Y92.01-)
  • transport vehicle as the place of occurrence of the external cause (Y92.81-)

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 T75 Other and unspecified effects of other external causes applies to 48 codes
  • The appropriate 7th character is to be added to each code from category T75
Values for category T75 Encounter: Initial, Subsequent, Sequela
  • 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.

CCSR INJ021
Effect of other external causes, initial encounter
Default principal diagnosis: inpatient Yes · outpatient Yes
CCSR EXT020
External cause codes: intent of injury, accidental/unintentional
Default principal diagnosis: inpatient No · outpatient No
CCSR EXT011
External cause codes: natural/environment; initial encounter
Default principal diagnosis: inpatient No · outpatient No

Convert T75.21XA to ICD-9-CMHistory

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

ICD-9-CM
994.9 Effect external caus NEC
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 T75.21XAOverview

What is the ICD-10 code for pneumatic hammer syndrome, initial encounter?

The ICD-10-CM code for pneumatic hammer syndrome, initial encounter is T75.21XA (sometimes written as T7521XA). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is T75.21XA (Pneumatic hammer syndrome) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report pneumatic hammer syndrome, initial encounter on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What does the 7th character A in T75.21XA mean?

The final character A marks the initial encounter: use it while the patient is receiving active treatment for pneumatic hammer syndrome, such as an emergency visit or first evaluation.

What MS-DRG does T75.21XA group to?

When pneumatic hammer syndrome, initial encounter is the principal diagnosis on an inpatient stay, it groups to MS-DRG 923, 922, with relative weights from 0.9980 to 1.6248 depending on complications. Higher weights mean higher Medicare reimbursement.

Can T75.21XA be reported with a code from T78?

Not as a rule. The Excludes1 note at T75, which applies to T75.21XA, lists "adverse effects NEC (T78.-)". An Excludes1 note means the excluded code is never reported together with this one; the only exception is when the two conditions are unrelated to each other (Official Guidelines, Section I.A.12.a).