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H20.12 ICD-10-CM Code: Chronic iridocyclitis, left eye

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

Coding at a Glance

Tabular directives
1 Excludes2 · 1 use-additional code

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 v44, 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 H20.12 in the official ICD-10-CM tabular list, quoted as published.

Source: CMS/CDC — ICD-10-CM Tabular ListRelease: FY2027Effective: October 1, 2026

Notes without a marker are published on H20.12 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 H20.1

Use Additional Code

Supplementary codes the tabular list directs you to add.

  • Use additional code for any associated cataract (H26.21-)

Source: inherited from H20.1

Coder workflow for H20.12

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

Before you code H20.12

  1. Laterality is coded in this family. Confirm the side documented — right, left, or bilateral — and select the matching code (this page’s code: left). The unspecified-side code applies only when the record states no side. Laterality is assigned from the documented side; where a bilateral code exists and both sides are documented, it is used instead of two unilateral codes (Guidelines I.B.13).

    ReviewH20.11 · right, H20.13 · bilateral, H20.10 · unspecified

    Guide: Laterality coding →

Choose the right path

  1. Is the side documented?
    Yes → Select the code for the documented side (or the bilateral code when both sides are documented and one exists).
    No → Use the unspecified-side code only when the record states no side; a query is the alternative.

    ReviewH20.11 · right, H20.13 · bilateral, H20.10 · unspecified

Consider H20.12. 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).
Laterality
Right, left or bilateral as documented; unspecified only when the record states no side (Guidelines I.B.13).
Acuity
Acute or chronic as documented; when both are documented and separate codes exist, both are reported with the acute code first (Guidelines I.B.8).
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

  • Excludes2 — not part of H20.12(1 note)

    Coding workflow: The conditions named in this note are not included in H20.12. When the record documents both, both may be reported; the note is a boundary, not a prohibition.

    CompareH30.2

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

  • Use Additional Code — after identifying H20.12(1 note)

    Coding workflow: Check whether the documentation supports the additional code(s) the note names, and report them with H20.12 when it does. Where the instruction is conditional (“if applicable”, “if known”), it applies only when the record documents the condition.

    ReviewH26.21

    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: The record documents the condition on one side only.

Coding question: Which code in this family applies?

Path: Select the sibling code for the documented side.

Reason: Laterality is assigned from the documented side; the unspecified-side code is for records that state no side (Guidelines I.B.13).

ReviewH20.11 · right, H20.13 · bilateral, H20.10 · unspecified

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

Coding question: Is a second code reported with H20.12?

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).

ReviewH26.21

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

Chronic iridocyclitis, left eye is a billable ICD-10-CM diagnosis code (H20.12).

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. Laterality is coded in this family. Confirm the documented side matches the code — the opposite-side siblings are in the relationships section. See the opposite-side sibling codes
  2. 1 Use Additional Code instruction — report the named additional code(s) when the documentation supports them. See the Use Additional Code 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

  • 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 H20.12 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 Code Also instruction: H26.21 — Cataract with neovascularization (via H20.1.-).

These codes suggest coding this condition alongside when both are present.

MS-DRG Grouper Relationships (FY2027)

Potential MS-DRG participation — not a DRG assignment.

FY2027 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):EYE004 — Uveitis and ocular inflammation (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 condition, opposite side

Same category and title, differing only in which side of the body is affected.

H20.10 — Chronic iridocyclitis, unspecified eye (unspecified)Compare H20.12 vs H20.10 →, H20.11 — Chronic iridocyclitis, right eye (right)Compare H20.12 vs H20.11 →, H20.13 — Chronic iridocyclitis, bilateral (bilateral)Compare H20.12 vs H20.13 →

Same clinical category (CCSR)

AHRQ's Clinical Classifications Software groups these diagnoses under the same clinical category (Uveitis and ocular inflammation).

H20.041 — Secondary noninfectious iridocyclitis, right eye, H20.042 — Secondary noninfectious iridocyclitis, left eye, H20.043 — Secondary noninfectious iridocyclitis, bilateral, H20.049 — Secondary noninfectious iridocyclitis, unspecified eye, H20.051 — Hypopyon, right eye, H20.052 — Hypopyon, left eye, H20.053 — Hypopyon, bilateral, H20.059 — Hypopyon, unspecified eye, H20.10 — Chronic iridocyclitis, unspecified eye, H20.11 — Chronic iridocyclitis, right eye, H20.13 — Chronic iridocyclitis, bilateral, H20.20 — Lens-induced iridocyclitis, unspecified eye, H20.21 — Lens-induced iridocyclitis, right eye, H20.22 — Lens-induced iridocyclitis, left eye, H20.23 — Lens-induced iridocyclitis, bilateral, H20.811 — Fuchs' heterochromic cyclitis, right eye, H20.812 — Fuchs' heterochromic cyclitis, left eye, H20.813 — Fuchs' heterochromic cyclitis, bilateral, H20.819 — Fuchs' heterochromic cyclitis, unspecified eye, H20.821 — Vogt-Koyanagi syndrome, right eye, +138 more

Same Index main term, other category

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

A18.54 — Tuberculous iridocyclitis (tuberculous), A51.43 — Secondary syphilitic oculopathy (syphilitic), A54.32 — Gonococcal iridocyclitis (gonococcal), B00.51 — Herpesviral iridocyclitis (in, herpesvirus), B02.32 — Zoster iridocyclitis (in, zoster), B89 — Unspecified parasitic disease (in, parasitic disease NOS), B99 — Other and unspecified infectious diseases (in, infectious disease NOS), D86.83 — Sarcoid iridocyclitis (in, sarcoidosis), M45.9 — Ankylosing spondylitis of unspecified sites in spine (in, ankylosing spondylitis)

Contextual Map

Every relationship of H20.12 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 H20.12 with this related code in Claim Check

Hierarchy

Referenced by Code Also 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 · FY2027

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 FY2027 tabular list, index and tables, effective October 1, 2026 Release, file and checksum · Publisher’s page
Claim edits Official source data
CMS Definitions of Medicare Code Edits — v44.0 (October 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 — v44 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. "H20.12 — Chronic iridocyclitis, left eye." ICD-10-CM FY2027. https://medcoder.ai/icd10/code/h20.12-chronic-iridocyclitis-left-eye

Change history

  • FY2016 — October 1, 2015
    In the code set at ICD-10-CM adoption
    Chronic iridocyclitis, left eye

No changes since FY2016 — additions, deletions, description changes and billable-status changes are tracked through FY2027, 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 H20.12 in its code family, with their registry titles.

View all codes in the H20 family