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K26 ICD-10-CM Code: Duodenal ulcer

Billing Status: NO. This is a clinician non-billable / parent hierarchy grouping in the ICD-10-CM system.

Coding at a Glance

Tabular directives
3 inclusion terms · 1 Excludes1 · 1 Excludes2 · 2 use-additional codes

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for K26 in the official ICD-10-CM tabular list, quoted as published.

Source: CMS/CDC — ICD-10-CM Tabular ListRelease: FY2026Effective: October 1, 2025

Notes without a marker are published on K26 itself; “inherited from” names the category or block whose note applies here.

Includes

Conditions the official ICD-10-CM tabular list includes under this code.

  • erosion (acute) of duodenum
  • duodenum ulcer (peptic)
  • postpyloric ulcer (peptic)

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).

Excludes2 — Not Included Here

Conditions not covered by this code, but which may be reported alongside it when both are present.

Source: inherited from K20-K31

Use Additional Code

Supplementary codes the tabular list directs you to add.

  • Use additional code to identify:
  • alcohol abuse and dependence (F10.-)

Coder workflow for K26

MedCoder structured workflow — derived from this code’s own official record

Before you code K26

  1. K26 is not reportable as written. Select the more specific code beneath it that the documentation supports. Codes are reported to the highest level of specificity the classification provides (Guidelines I.B.2).

    ReviewK26.0, K26.1, K26.2, K26.3, K26.4, K26.5, K26.6, K26.7, K26.9

    See the relationships section · Guide: How to choose an ICD-10-CM code →

  2. Check the Excludes1 note: if the documentation supports a condition named there, do not simply proceed with K26. Excludes1 conditions are not reported together with this code unless the record shows they are unrelated (Guidelines I.A.12.a).

    See the official tabular notes

Choose the right path

  1. Does the documentation support one of the more specific codes beneath K26?
    Yes → Select that code and continue the checks below on its own page.
    No → K26 cannot be reported as written; query for the specificity its subcategory needs.

    ReviewK26.0, K26.1, K26.2, K26.3, K26.4, K26.5, K26.6, K26.7, K26.9

  2. Does the documentation support a condition named in K26’s Excludes1 note?
    Yes → Do not simply proceed: review the excluded code. Both are reported only when the record shows the two conditions are unrelated.
    No → Continue.

    ReviewK27

Consider K26. Then work the Use Additional Code note, and confirm the code is valid for the date of service in the Verify section.

Documentation check

The provider’s diagnostic statement
Codes are assigned from the provider’s documented diagnosis, not from clinical criteria, test values or a medication list (Guidelines I.A.19).
The conditions the Use Additional Code note names
Reported with this code when documented; a conditional instruction (“if applicable”, “if known”) applies only when the record supports it.

Official instructions as workflow

  • Excludes1 — check before selecting K26(1 note)

    Coding workflow: If the documentation supports a condition named in this note, do not simply proceed with K26: the two are not reported together. The one exception is when the record shows the two conditions are unrelated to each other.

    CompareK27

    See the official tabular notes · Guidelines I.A.12.a

  • Excludes2 — not part of K26(1 note)

    Coding workflow: The conditions named in this note are not included in K26. When the record documents both, both may be reported; the note is a boundary, not a prohibition.

    CompareK44

    See the official tabular notes · Guidelines I.A.12.b

  • Use Additional Code — after identifying K26(2 notes)

    Coding workflow: Check whether the documentation supports the additional code(s) the note names, and report them with K26 when it does. Where the instruction is conditional (“if applicable”, “if known”), it applies only when the record documents the condition.

    ReviewF10

    See the official tabular notes · Guidelines I.A.13

Coding decision scenarios

Pattern scenarios for this code’s structure — decision rules, not clinical cases

Documentation: Both the condition K26 describes and a condition named in its Excludes1 note are documented for the same encounter.

Coding question: Can both codes be reported?

Path: Review the Excludes1 note and the excluded code, and look for a provider statement on whether the two conditions are related.

Reason: Excludes1 means the two are not coded together; the exception is when the record shows the conditions are unrelated to each other (Guidelines I.A.12.a).

ReviewK27

Documentation: A condition the Use Additional Code note names is documented.

Coding question: Is a second code reported with K26?

Path: Review the Use Additional Code note and the code it names.

Reason: The additional code is reported when the record documents the condition; a conditional instruction applies only when its condition is met (Guidelines I.A.13).

ReviewF10

Every row is derived from this code’s own record — its title, tabular notes, 7th-character family and same-category siblings — with fixed MedCoder wording; nothing is inferred about a patient. The official notes and guideline text are in the sections each row links to, and they control.

Code Overview

Duodenal ulcer is a non-billable ICD-10-CM category code (K26). A more specific billable subcode must be selected for claims submission.

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. 2 Use Additional Code instructions — report the named additional code(s) when the documentation supports them. See the Use Additional Code notes
  2. 1 Excludes1 entry — codes named there are generally not reported together with this code (Guidelines I.A.12.a). See the Excludes1 notes
  3. 1 Excludes2 entry — those conditions are not part of this code and may be reported additionally when documented. See the Excludes2 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

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

MedCoder structured relationships — computed from published CMS and AHRQ datasets

Other codes that name K26 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 3 Excludes1 notes: K63.1 — Perforation of intestine (nontraumatic), K63.3 — Ulcer of intestine, K92.2 — Gastrointestinal hemorrhage, unspecified.

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

Contextual Map

Every relationship of K26 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 K26 with these 6 related codes in Claim Check

Hierarchy

Excludes1

Excludes2

Use Additional Code

Referenced by Excludes1 notes

Nearest codes (9)

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

Can K26 be billed directly?

No. K26 (Duodenal ulcer) is a non-billable ICD-10-CM category code. A more specific billable subcode must be selected based on clinical documentation.

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

Cite this page

Reference this page in a research guide, syllabus or article. The release is included because code content changes each year.

MedCoder.ai. "K26 — Duodenal ulcer." ICD-10-CM FY2026. https://medcoder.ai/icd10/code/k26-duodenal-ulcer

Change history

  • FY2016 — October 1, 2015
    In the code set at ICD-10-CM adoption
    Duodenal ulcer

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 K26 in its code family, with their registry titles.