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W21.4XXS ICD-10-CM Code: Striking against diving board, sequela

Billing Status: YES. This is a valid, specific, and billable ICD-10-CM reference.

Coding at a Glance

7th character
Required — see the character table on this page
Tabular directives
6 Excludes1 · 1 use-additional code

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for W21.4XXS in the official ICD-10-CM tabular list, quoted as published.

Notes without a marker are published on W21.4XXS itself; “inherited from” names the category or block whose note applies here.

Excludes1 — Not Coded Here

Conditions generally not reported together with this code (Excludes1) -- an error unless the two conditions are documented as unrelated to each other (ICD-10-CM Official Guidelines, Section I.A.12.a).

Use Additional Code

Supplementary codes the tabular list directs you to add.

  • Use additional code for subsequent falling into water, if applicable (W16.-)

Source: inherited from W21.4

7th Character Guide

"The appropriate 7th character is to be added to each code from category W21"

  • A — initial encounter
  • D — subsequent encounter
  • S — sequela (this page’s code)

How the encounter character is assigned. “Initial encounter” means the patient is receiving active treatment for the condition — it is not limited to the first visit, and a different or new provider giving active treatment still assigns it. “Subsequent encounter” covers care during the healing or recovery phase after active treatment. “Sequela” is for complications or conditions that arise as a direct result of the original condition.

ICD-10-CM Official Guidelines for Coding and Reporting, Section I.C.19.a (paraphrased by MedCoder).

Variant codes in this family

W21.4XXA, W21.4XXD, W21.4XXS

Character meanings are CMS's official 7th-character extensions for this family, as carried in each variant code's official description; variant codes are registry rows. The explanation of how the encounter character is assigned is MedCoder editorial, distinct from the official content above it.

Code Overview

Striking against diving board, sequela is a billable ICD-10-CM diagnosis code (W21.4XXS).

MedCoder summary Summary composed by MedCoder from this code's official ICD-10-CM record. The tabular instructional notes themselves appear verbatim below.

Decision Points

The directives on this code's own record, as a pre-claim checklist.

  1. A 7th character applies in this family. Confirm the documented encounter matches the character assigned. See the official 7th-character definitions and this code’s variants
  2. 1 Use Additional Code instruction — report the named additional code(s) when the documentation supports them. See the Use Additional Code notes
  3. 6 Excludes1 entries — codes named there are generally not reported together with this code (Guidelines I.A.12.a). See the Excludes1 notes

Checklist rows are derived from this code's own official directives; the wording of each check is MedCoder editorial. The official notes themselves are in the sections each row links to.

Verify Before Coding

  • Principal-diagnosis restriction. External cause of morbidity codes (V, W, X and Y) describe the circumstance that caused an injury, not the condition treated. The Medicare Code Editor rejects them as a principal diagnosis; sequence the injury or condition first and report this code as secondary.

From the code registry, the Medicare Code Editor, and the MS-DRG Definitions Manual. Check it against a full claim in Claim Check.

Relationships & Classification

Other codes that name W21.4XXS or its code family, from the CMS ICD-10-CM tabular instructional notes. Tabular-note edges are stored at the code family level that carries each note.

Referenced by 2 Excludes1 notes: W20 — Struck by thrown, projected or falling object (via W21.-), W50 — Accidental hit, strike, kick, twist, bite or scratch by another person (via W21.-).

These codes’ tabular lists mark this diagnosis as mutually exclusive — not reported together unless the conditions are documented as unrelated.

Referenced by 1 Excludes2 note: W45 — Foreign body or object entering through skin (via W21.-).

These codes’ tabular lists name this diagnosis as distinct — both may be reported when both are documented.

Clinical classification (AHRQ CCSR):EXT030 — External cause codes: sequela.

Clinical Classifications Software Refined (CCSR) for ICD-10-CM Diagnoses. Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality.

Related Codes

Same clinical category (CCSR)

AHRQ's Clinical Classifications Software groups these diagnoses under the same clinical category (External cause codes: sequela).

+2321 more

Contextual Map

Every relationship of W21.4XXS in one view: hierarchy, official tabular instructions in both directions, clinical classification, risk adjustment, MS-DRG participation, index terms and change history — each edge carrying the CMS source it derives from.

Hierarchy

Referenced by Excludes1 notes

Referenced by Excludes2 notes

Clinical classification (CCSR)

Nearest codes (40)

Change history

  • FY2016 — In the code set at ICD-10-CM adoption [Change history]

Common coding questions

Does W21.4XXS require a 7th character?

Yes. The appropriate 7th character is to be added to each code from category W21.

Sources for this page

Every coding fact on this page is read from the datasets below. Nothing is AI-generated; MedCoder-derived relationships and editorial are labelled where they appear.

Code, title, tabular notes and index terms
CMS/CDC ICD-10-CM FY2026 tabular list, index and tables, effective October 1, 2025
Claim edits
CMS Definitions of Medicare Code Edits — v43.1 (April 2026)
Change history and date-of-service validity
CMS ICD-10-CM release addenda, ingested release by release into the change ledger
Comparisons, relationships and the contextual map MedCoder-derived
Derived by MedCoder from the tabular notes and tables above; every derived relationship is marked as derived where it appears

All data sources and release dates

Change history

  • FY2016 — October 1, 2015
    In the code set at ICD-10-CM adoption
    Striking against diving board, sequela

No changes since FY2016 — additions, deletions, description changes and billable-status changes are tracked through FY2027 (effective October 1, 2026), and none are recorded for this code. Note changes are tracked from FY2027 only.

Nearest Codes in This Family

Official ICD-10-CM classifications closest to W21.4XXS in its code family, with their registry titles.

View all codes in the W21 family