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H40.20X1 ICD-10-CM Code: Unspecified primary angle-closure glaucoma, mild stage

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
5 Excludes1
Risk adjustment
RxHCC V08 category 244

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 H40.20X1 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 H40.20X1 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

"One of the following 7th characters is to be assigned to code H40.20 to designate the stage of glaucoma"

  • 0 — stage unspecified
  • 1 — mild stage (this page’s code)
  • 2 — moderate stage
  • 3 — severe stage
  • 4 — indeterminate stage

Variant codes in this family

H40.20X0, H40.20X1, H40.20X2, H40.20X3, H40.20X4

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.

Coder workflow for H40.20X1

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

Before you code H40.20X1

  1. Unspecified does not mean incorrect. When the record gives no greater specificity, H40.20X1 may be the appropriate code. Check the record for detail that supports a more specific sibling — in this subcategory the siblings differ by severity, stage. An unspecified code is for records that do not provide the detail a more specific code needs; a query, not an assumption, is the route to specificity (Guidelines I.A.9.b, I.B.18).

    See the relationships section · Guide: Other vs unspecified (NEC vs NOS) →

  2. A 7th character is required in this family. Confirm the documentation supports the character assigned — its meaning in this family is defined in the official instruction. This page’s code carries “1”. The official 7th-character definitions for this family are quoted in the guide.

    See the 7th Character Guide

  3. Check the Excludes1 note: if the documentation supports a condition named there, do not simply proceed with H40.20X1. 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 record document the detail a more specific sibling code needs?
    Yes → Review the specific siblings in this subcategory.
    No → Continue — H40.20X1 is appropriate when the documentation goes no further.
  2. Does the documentation support a condition named in H40.20X1’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.

    ReviewH40.83, H44.51, Q15.0, P15.3

  3. Does the documentation support one of this family’s 7th-character values?
    Yes → Assign the matching 7th character; the variant codes are in the 7th Character Guide.
    No → The code is invalid without its 7th character — query for the missing element.

Consider H40.20X1. Then 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).
7th-character basis
The documented element this family’s 7th character records (see the official definitions in the 7th Character Guide).
Severity
Mild, moderate or severe as the provider states it; severity is not inferred from the clinical picture.
Stage
The documented stage decides the sibling code; where a Use Additional Code note asks for a stage code, report it as well.
Any detail beyond this code’s title
What the record states that a more specific sibling code would capture — or its absence, which itself supports the unspecified code.

Official instructions as workflow

  • Excludes1 — check before selecting H40.20X1(5 notes)

    Coding workflow: If the documentation supports a condition named in this note, do not simply proceed with H40.20X1: the two are not reported together. The one exception is when the record shows the two conditions are unrelated to each other.

    CompareH40.83, H44.51, Q15.0, P15.3

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

Coding decision scenarios

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

Documentation: The provider documents the condition in the terms of this code’s title and records no further detail.

Coding question: Is a more specific sibling code supportable?

Path: Review the subcategory for a sibling that names the missing detail.

Reason: A more specific code needs documentation of the distinguishing element; without it the unspecified code is appropriate, and a provider query is the route to specificity (Guidelines I.A.9.b, I.B.18).

Documentation: Both the condition H40.20X1 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).

ReviewH40.83, H44.51, Q15.0, P15.3

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

Unspecified primary angle-closure glaucoma, mild stage is a billable ICD-10-CM diagnosis code (H40.20X1).

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

Official Coding Guidelines

Official source data — quoted verbatim from the CMS/NCHS Official Guidelines

Official source data — quoted verbatim from the CMS/NCHS Official Guidelines

Verbatim excerpts from the ICD-10-CM Official Guidelines for Coding and Reporting (CMS/NCHS) that govern this code.

Chapter 7: Diseases of the Eye and Adnexa (H00-H59)

When a patient has bilateral glaucoma and both eyes are documented as being the same type and stage, and the classification does not provide a code for bilateral glaucoma (i.e. subcategories H40.10, and H40.20)

Chapter 7: Diseases of the Eye and Adnexa (H00-H59)

When a patient has bilateral glaucoma and each eye is documented as having a different type, and the classification does not distinguish laterality (i.e., subcategories H40.10, and H40.20), assign one code for each type of glaucoma with the appropriate seventh character for the stage.

Chapter 7: Diseases of the Eye and Adnexa (H00-H59)

When a patient has bilateral glaucoma and each eye is documented as having the same type, but different stage, and the classification does not distinguish laterality (i.e., subcategories H40.10 and H40.20), assign a code for the type of glaucoma for each eye with the seventh character for the specific glaucoma stage documented for each eye.

Chapter 7: Diseases of the Eye and Adnexa (H00-H59)

1) Assigning Glaucoma Codes Assign as many codes from category H40, Glaucoma, as needed to identify the type of glaucoma, the affected eye, and the glaucoma stage.

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 H40.20X1 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 First instruction: H26.23 — Glaucomatous flecks (subcapsular) (via H40.-).

Each of these codes carries a Code First note naming this condition — when that code is reported, THIS code is sequenced first, ahead of it.

Referenced by 5 Use Additional Code instructions: E08.39 — Diabetes mellitus due to underlying condition with other diabetic ophthalmic complication (via H40.-), E09.39 — Drug or chemical induced diabetes mellitus with other diabetic ophthalmic complication (via H40.-), E10.39 — Type 1 diabetes mellitus with other diabetic ophthalmic complication (via H40.-), E11.39 — Type 2 diabetes mellitus with other diabetic ophthalmic complication (via H40.-), E13.39 — Other specified diabetes mellitus with other diabetic ophthalmic complication (via H40.-).

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):EYE003 — Glaucoma (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 (Glaucoma).

H40.1490 — Capsular glaucoma with pseudoexfoliation of lens, unspecified eye, stage unspecified, H40.1491 — Capsular glaucoma with pseudoexfoliation of lens, unspecified eye, mild stage, H40.1492 — Capsular glaucoma with pseudoexfoliation of lens, unspecified eye, moderate stage, H40.1493 — Capsular glaucoma with pseudoexfoliation of lens, unspecified eye, severe stage, H40.1494 — Capsular glaucoma with pseudoexfoliation of lens, unspecified eye, indeterminate stage, H40.151 — Residual stage of open-angle glaucoma, right eye, H40.152 — Residual stage of open-angle glaucoma, left eye, H40.153 — Residual stage of open-angle glaucoma, bilateral, H40.159 — Residual stage of open-angle glaucoma, unspecified eye, H40.20X0 — Unspecified primary angle-closure glaucoma, stage unspecified, H40.20X2 — Unspecified primary angle-closure glaucoma, moderate stage, H40.20X3 — Unspecified primary angle-closure glaucoma, severe stage, H40.20X4 — Unspecified primary angle-closure glaucoma, indeterminate stage, H40.211 — Acute angle-closure glaucoma, right eye, H40.212 — Acute angle-closure glaucoma, left eye, H40.213 — Acute angle-closure glaucoma, bilateral, H40.219 — Acute angle-closure glaucoma, unspecified eye, H40.2210 — Chronic angle-closure glaucoma, right eye, stage unspecified, H40.2211 — Chronic angle-closure glaucoma, right eye, mild stage, H40.2212 — Chronic angle-closure glaucoma, right eye, moderate stage, +252 more

Same Index main term, other category

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

A18.59 — Other tuberculosis of eye (tuberculous), A52.71 — Late syphilitic oculopathy (syphilitic), B73.02 — Onchocerciasis with glaucoma (in, onchocerciasis), E34.9 — Endocrine disorder, unspecified (in, endocrine disease NOS), E72.03 — Lowe's syndrome (in, Lowe's syndrome), E85.4 — Organ-limited amyloidosis (in, amyloidosis), E88.9 — Metabolic disorder, unspecified (in, metabolic disease NOS), H44.51 — Absolute glaucoma (absolute), P15.3 — Birth injury to eye (traumatic, newborn), Q13.1 — Absence of iris (in, aniridia), Q13.81 — Rieger anomaly (in, Rieger anomaly), Q15.0 — Congenital glaucoma (newborn)

Contextual Map

Every relationship of H40.20X1 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 H40.20X1 with these 6 related codes in Claim Check

Hierarchy

Referenced by Code First instructions

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

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 H40.20X1 require a 7th character?

Yes. One of the following 7th characters is to be assigned to code H40.20 to designate the stage of glaucoma.

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
Coding guidelines Official source data
ICD-10-CM Official Guidelines for Coding and Reporting (FY2026), quoted by section 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. "H40.20X1 — Unspecified primary angle-closure glaucoma, mild stage." ICD-10-CM FY2026. https://medcoder.ai/icd10/code/h40.20x1-unspecified-primary-angle-closure-glaucoma-mild-stage

Change history

  • FY2016 — October 1, 2015
    In the code set at ICD-10-CM adoption
    Unspecified primary angle-closure glaucoma, mild stage

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 H40.20X1 in its code family, with their registry titles.

View all codes in the H40 family