Is ICD-10-CM code W21 billable?

No, W21 (Striking against or struck by sports equipment) is a non-billable ICD-10-CM code. It must be coded to a more specific subcategory before it can be used for reimbursement.

What chapter does ICD-10-CM code W21 belong to?

W21 belongs to Chapter 20 of the ICD-10-CM tabular list: V00–Y99 (External Causes of Morbidity).

W21Not billable, use a more specific code below

Striking against or struck by sports equipment

In Exposure to inanimate mechanical forces (W20-W49), chapter 20: External Causes of Morbidity

72 billable codes under W21: none are a CC or MCC; none map to an HCC.

Instructional notes

Excludes1: not coded here, use a different code

assault with sports equipment (Y08.0-)
striking against or struck by sports equipment with subsequent fall (W18.01)

Also applies, from Exposure to inanimate mechanical forces (W20-W49)

These notes sit on W20-W49 and apply to every code under it, including W21.

Excludes1: not coded here, use a different code

assault (X92-Y09)
contact or collision with animals or persons (W50-W64)
exposure to inanimate mechanical forces involving military or war operations (Y36.-, Y37.-)
intentional self-harm (X71-X83)

Official coding guidelines

From the ICD-10-CM Official Guidelines for Coding and Reporting, FY 2027 (CMS and NCHS). Links open the PDF at the right page.

Covers how to report external cause codes (V00-Y99) describing cause, intent, place, activity, and status. They are never principal or first-listed, and reporting is voluntary unless required.

General External Cause Coding Guidelines (page 88)
Place of Occurrence Guideline (page 89)
Activity Code (page 89)
Place of Occurrence, Activity, and Status Codes Used with other External Cause Code (page 89)
If the Reporting Format Limits the Number of External Cause Codes (page 90)
Multiple External Cause Coding Guidelines (page 90)
Child and Adult Abuse Guideline (page 90)
Unknown or Undetermined Intent Guideline (page 91)

Read Section I.C.20 (page 87), 3 more topics

All codes under W21

W21 can't be used on a claim. Pick a billable code below; grey headings group them.

W21 MS-DRGs

This code does not group to an MS-DRG as a principal diagnosis.

Other codes that refer to W21

Notes on these codes point to W21.

W20 Excludes1: struck by thrown sports equipment (W21.-)
W20.8 Excludes1: struck by thrown sports equipment (W21.-)

About the condition

Plain-language background from MedlinePlus (National Library of Medicine), not coding guidance.

Sports Injuries

Exercising is good for you, but sometimes you can injure yourself when you play sports or exercise. Accidents, poor training practices, or improper gear can cause them. Some people get hurt because they are not in shape. Not warming up or stretching enough can also lead to injuries.

Sports Safety

Playing sports can be fun, but it can also be dangerous if you are not careful. You can help prevent injuries by: If you have already hurt yourself playing a sport, make sure you recover completely before you start up again. If possible, protect the injured part of your body with padding, a brace, or special equipment. When you do start playing again, start slowly.

Code history

Valid since FY2016, when ICD-10-CM took effect on October 1, 2015. No changes since.