2026 ICD-10-CM Diagnosis Code H16.312Corneal abscess, left eye

ICD-10-CM Codes›H00–H59›H15-H22›H16

ICD-10-CM H16.312
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

H16.312 is a billable ICD-10-CM diagnosis code for corneal abscess, left eye. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 121 through 122. Coders also document this condition as corneal abscess. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Cornea and external disease.

Code Identity

ICD-10-CM Code
H16.312
Billable Status
Yes — Valid for Submission
Code Describes
Corneal abscess, left eye
Short Description
Corneal abscess, left eye
Same as the full description in the CMS dataset.
Parent Code
H16.31
Corneal abscess

Code Classification

ChapterH00–H59Diseases of the eye and adnexa
SectionH15-H22Disorders of sclera, cornea, iris and ciliary body
CategoryH16Keratitis
This CodeH16.312Corneal abscess, left eye

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Corneal abscess
  • Left corneal abscess

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

  • Corneal Abscess

    an abscess of the cornea.

Patient EducationClinical

Abscess

An abscess is a pocket of pus. You can get an abscess almost anywhere in your body. When an area of your body becomes infected, your body's immune system tries to fight the infection. White blood cells go to the infected area, collect within the damaged tissue, and cause inflammation. During this process, pus forms.

Read the full article at MedlinePlus

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

Convert H16.312 to ICD-9-CMHistory

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

ICD-9-CM
370.55 Corneal abscess
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 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About H16.312Overview

Is H16.312 (Corneal abscess) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report corneal abscess, left eye on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does H16.312 group to?

When corneal abscess, left eye is the principal diagnosis on an inpatient stay, it groups to MS-DRG 121, 122, with relative weights from 0.7858 to 1.1633 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of H16.312?

Under the General Equivalence Mappings, corneal abscess, left eye converts to ICD-9-CM 370.55 (corneal abscess). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.