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H31.21 ICD-10-CM Code: Choroideremia

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

Coding at a Glance

Tabular directives
2 Excludes2

Inpatient Payment Groups (MS-DRG)

Potential MS-DRG participation — not a DRG assignment.

MS-DRGs this diagnosis helps define, as principal or secondary, per the CMS ICD-10-CM/PCS MS-DRG Definitions Manual v43, Appendix B.

  • MS-DRG 124 — OTHER DISORDERS OF THE EYE WITH MCC OR THROMBOLYTIC AGENT (MDC 02)
  • MS-DRG 125 — OTHER DISORDERS OF THE EYE WITHOUT MCC (MDC 02)

A diagnosis appearing in a group's logic does not by itself determine the DRG assigned to a stay; the grouper uses the full claim.

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for H31.21 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 H31.21 itself; “inherited from” names the category or block whose note applies here.

Excludes2 — Not Included Here

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

Source: inherited from H31.2

Coder workflow for H31.21

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

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).

Official instructions as workflow

  • Excludes2 — not part of H31.21(2 notes)

    Coding workflow: The conditions named in this note are not included in H31.21. When the record documents both, both may be reported; the note is a boundary, not a prohibition.

    CompareE72.4

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

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

Choroideremia is a billable ICD-10-CM diagnosis code (H31.21).

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

Indexed Clinical Terms (2)

Official source data — entries quoted as published, in the Index’s own lookup phrasing

Clinical term phrases from the official ICD-10-CM Index to Diseases and Injuries that map to this code. These are alphabetic-index entries shown as the Index writes them — lookup phrasing, not necessarily the wording of a final diagnosis.

Verify Before Coding

  • No Medicare Code Editor or MS-DRG Definitions Manual restrictions apply to this code.

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 H31.21 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 1 Excludes1 note: E72.4 — Disorders of ornithine metabolism (via H31.2.-).

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

Referenced by 1 Use Additional Code instruction: H44.2A — Degenerative myopia with choroidal neovascularization (via H31.-).

These codes instruct coders to additionally report this code when it applies.

MS-DRG Grouper Relationships (FY2026)

Potential MS-DRG participation — not a DRG assignment.

FY2026 MS-DRG: not on the CMS CC/MCC list — as a secondary diagnosis this code does not change MS-DRG severity for that release.

Named in the grouper logic of 2 MS-DRGs: DRG 124 (MDC 02), DRG 125 (MDC 02).

From the CMS MS-DRG Definitions Manual (Appendices B and C). Actual DRG assignment depends on the complete claim.

Clinical classification (AHRQ CCSR):EYE005 — Retinal and vitreous conditions (default).

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 (Retinal and vitreous conditions).

+747 more

Same Index main term, other category

The ICD-10-CM Index to Diseases and Injuries files this code under the main term “Dystrophy, dystrophia”; these codes share that main term but sit in a different category of the Tabular List.

G71.09 — Other specified muscular dystrophies (ocular), G71.11 — Myotonic muscular dystrophy (muscular, myotonic), G90.2 — Horner's syndrome (cervical sympathetic), H18.50 — Unspecified hereditary corneal dystrophies (cornea), H18.51 — Endothelial corneal dystrophy (Fuchs'), H18.52 — Epithelial (juvenile) corneal dystrophy (cornea, epithelial), H18.53 — Granular corneal dystrophy (cornea, granular), H18.54 — Lattice corneal dystrophy (cornea, lattice), H18.55 — Macular corneal dystrophy (cornea, macular), H18.59 — Other hereditary corneal dystrophies (cornea, specified type NEC), H35.50 — Unspecified hereditary retinal dystrophy (retinal), H35.51 — Vitreoretinal dystrophy (vitreoretinal), H35.52 — Pigmentary retinal dystrophy (retinal, pigmentary), H35.53 — Other dystrophies primarily involving the sensory retina (retinal, involving, sensory area), H35.54 — Dystrophies primarily involving the retinal pigment epithelium (tapetoretinal), L60.3 — Nail dystrophy (nail), L67.8 — Other hair color and hair shaft abnormalities (hair), L98.8 — Other specified disorders of the skin and subcutaneous tissue (skin NEC), N83.8 — Other noninflammatory disorders of ovary, fallopian tube and broad ligament (ovarian), N90.4 — Leukoplakia of vulva (vulva), +22 more

Contextual Map

Every relationship of H31.21 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 H31.21 with these 2 related codes in Claim Check

Hierarchy

Referenced by Excludes1 notes

Referenced by Use Additional Code instructions

Clinical classification (CCSR)

MS-DRG Grouper

MDC crossing

  • MDC 02 — Diseases and Disorders of the Eye[MDC crossing]: “Diseases and Disorders of the Eye — the grouper's crossing between diagnoses and procedures: a principal diagnosis sets the MDC, and same-MDC procedures move the stay to its surgical DRGs. 1,200 same-MDC procedures group here; browse them on the MDC page.”— CMS MS-DRG Definitions Manual · FY2026

Index entries

  • Choroideremia[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Dystrophy, dystrophia, choroid (hereditary), choroideremia[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026

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

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
Inpatient payment groups Official source data
CMS MS-DRG Definitions Manual (incl. Appendix B diagnosis index, Appendix C CC/MCC list, Appendix E procedure index) and IPPS Final Rule tables — v43 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. "H31.21 — Choroideremia." ICD-10-CM FY2026. https://medcoder.ai/icd10/code/h31.21-choroideremia

Change history

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

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 H31.21 in its code family, with their registry titles.

View all codes in the H31 family