2027 ICD-10-CM Diagnosis Code H10.421Simple chronic conjunctivitis, right eye

ICD-10-CM Codes›H00–H59›H10-H11›H10

ICD-10-CM H10.421
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

H10.421 is a billable ICD-10-CM diagnosis code for simple chronic conjunctivitis, right eye. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 124 through 125. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Cornea and external disease.

Code Identity

ICD-10-CM Code
H10.421
Billable Status
Yes — Valid for Submission
Code Describes
Simple chronic conjunctivitis, right eye
Short Description
Simple chronic conjunctivitis, right eye
Same as the full description in the CMS dataset.
Parent Code
H10.42
Simple chronic conjunctivitis

Code Classification

ChapterH00–H59Diseases of the eye and adnexa
SectionH10-H11Disorders of conjunctiva
CategoryH10Conjunctivitis
This CodeH10.421Simple chronic conjunctivitis, right eye

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to H10.421: its own notes plus those printed at H10 and Chapter 7. A note printed at a category, block or chapter applies to every code under it.

Excludes1

Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.

From H10 Conjunctivitis applies to 72 codes

Excludes2

Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.

From Chapter 7 (H00-H59) Diseases of the eye and adnexa applies to 2,677 codes
  • certain conditions originating in the perinatal period (P04-P96)
  • certain infectious and parasitic diseases (A00-B99)
  • complications of pregnancy, childbirth and the puerperium (O00-O9A)
  • congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)
  • diabetes mellitus related eye conditions (E09.3-, E10.3-, E11.3-, E13.3-)
  • endocrine, nutritional and metabolic diseases (E00-E88)
  • injury (trauma) of eye and orbit (S05.-)
  • injury, poisoning and certain other consequences of external causes (S00-T88)
  • neoplasms (C00-D49)
  • symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)
  • syphilis related eye disorders (A50.01, A50.3-, A51.43, A52.71)

Notes

General instructions on how these codes are used.

From Chapter 7 (H00-H59) Diseases of the eye and adnexa applies to 2,677 codes
  • Use an external cause code following the code for the eye condition, if applicable, to identify the cause of the eye condition

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR EYE001
Cornea and external disease
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Conjunctivitis

    inflammation of the conjunctiva.

Patient EducationClinical

Pink Eye

Conjunctivitis is the medical name for pink eye. It involves inflammation of the outer layer of the eye and inside of the eyelid. It can cause swelling, itching, burning, discharge, and redness. Causes include:

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert H10.421 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
372.11 Simpl chr conjunctivitis
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About H10.421Overview

What is the ICD-10 code for simple chronic conjunctivitis, right eye?

The ICD-10-CM code for simple chronic conjunctivitis, right eye is H10.421 (sometimes written as H10421). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is H10.421 (Simple chronic conjunctivitis) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report simple chronic conjunctivitis, right eye on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does H10.421 group to?

When simple chronic conjunctivitis, right eye is the principal diagnosis on an inpatient stay, it groups to MS-DRG 125, 124, with relative weights from 0.7699 to 1.2470 depending on complications. Higher weights mean higher Medicare reimbursement.

Can H10.421 be reported with a code from H16.2?

Not as a rule. The Excludes1 note at H10, which applies to H10.421, lists "keratoconjunctivitis (H16.2-)". An Excludes1 note means the excluded code is never reported together with this one; the only exception is when the two conditions are unrelated to each other (Official Guidelines, Section I.A.12.a).

What is the ICD-9 equivalent of H10.421?

Under the General Equivalence Mappings, simple chronic conjunctivitis, right eye converts to ICD-9-CM 372.11 (simpl chr conjunctivitis). The mapping is approximate, so confirm the match fits the documentation.