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W56.51XD ICD-10-CM Code: Bitten by other fish, subsequent encounter

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
2 Excludes1

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for W56.51XD in the official ICD-10-CM tabular list, quoted as published.

Notes without a marker are published on W56.51XD 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).

7th Character Guide

"The appropriate 7th character is to be added to each code from category W56"

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

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

W56.51XA, W56.51XD, W56.51XS

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

Bitten by other fish, subsequent encounter is a billable ICD-10-CM diagnosis code (W56.51XD).

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

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 W56.51XD 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 28 Excludes1 notes: W20 — Struck by thrown, projected or falling object (via W56.-), W20-W49 — Exposure to inanimate mechanical forces (W20-W49) (via W56.-), W21 — Striking against or struck by sports equipment (via W56.-), W22 — Striking against or struck by other objects (via W56.-), W23 — Caught, crushed, jammed or pinched in or between objects (via W56.-), W24 — Contact with lifting and transmission devices, not elsewhere classified (via W56.-), W25 — Contact with sharp glass (via W56.-), W26 — Contact with other sharp objects (via W56.-), W27 — Contact with nonpowered hand tool (via W56.-), W28 — Contact with powered lawn mower (via W56.-), W29 — Contact with other powered hand tools and household machinery (via W56.-), W30 — Contact with agricultural machinery (via W56.-), W31 — Contact with other and unspecified machinery (via W56.-), W32 — Accidental handgun discharge and malfunction (via W56.-), W33 — Accidental rifle, shotgun and larger firearm discharge and malfunction (via W56.-), W34 — Accidental discharge and malfunction from other and unspecified firearms and guns (via W56.-), W35 — Explosion and rupture of boiler (via W56.-), W36 — Explosion and rupture of gas cylinder (via W56.-), W37 — Explosion and rupture of pressurized tire, pipe or hose (via W56.-), W38 — Explosion and rupture of other specified pressurized devices (via W56.-), +8 more.

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

Clinical classification (AHRQ CCSR):EXT029 — External cause codes: subsequent encounter.

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: subsequent encounter).

+2321 more

Contextual Map

Every relationship of W56.51XD 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.

Run W56.51XD with these 8 related codes in Claim Check

Hierarchy

Referenced by Excludes1 notes (28)

Clinical classification (CCSR)

Nearest codes (40)

Change history

  • FY2016 — In the code set at ICD-10-CM adoption [Change history]— CMS release files (code change ledger) · icd10cm-fy2016

Common coding questions

Does W56.51XD require a 7th character?

Yes. The appropriate 7th character is to be added to each code from category W56.

Sources for this page

Codes, titles, notes, index terms and mappings on this page are transcribed from the datasets below. Relationships MedCoder computed and text MedCoder wrote are labelled where they appear.

Code, title, tabular notes and index terms Official source data
CMS/CDC ICD-10-CM FY2026 tabular list, index and tables, effective October 1, 2025 Release, file and checksum · Publisher’s page
Claim edits Official source data
CMS Definitions of Medicare Code Edits — v43.1 (April 2026) Release, file and checksum · Publisher’s page
Change history and date-of-service validity Official source data
CMS ICD-10-CM release addenda, ingested release by release into the change ledger Release, file and checksum · Publisher’s page
Comparisons, relationships and the contextual map MedCoder structured relationship
Computed by MedCoder from the tabular notes and tables above; every derived relationship is marked as derived where it appears
Summary and FAQ answers MedCoder explanation
Written by MedCoder to explain the sources above: drafted with AI assistance, checked by a person against the release files, and labelled as MedCoder text where it appears. Not official text.

Labels on this page: Official source data · MedCoder structured relationship · MedCoder explanation. How to read the labels · All data sources and release dates

Change history

  • FY2016 — October 1, 2015
    In the code set at ICD-10-CM adoption
    Bitten by other fish, subsequent encounter

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 W56.51XD in its code family, with their registry titles.

View all codes in the W56 family