2026 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 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

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 2026 (October 1, 2025 through September 30, 2026) 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 2026, published by CMS and the National Center for Health Statistics.

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 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About T75.21XAOverview

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, 2025 through September 30, 2026.

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 922, 923, with relative weights from 1.0177 to 1.7494 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of T75.21XA?

Under the General Equivalence Mappings, pneumatic hammer syndrome, initial encounter converts to ICD-9-CM 994.9 (effect external caus NEC). 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.