2026 ICD-10-CM Diagnosis Code T86.8409Corneal transplant rejection, unspecified eye

ICD-10-CM Codes›S00–T88›T80-T88›T86

ICD-10-CM T86.8409
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

T86.8409 is a billable ICD-10-CM diagnosis code for corneal transplant rejection, unspecified eye. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 124 through 125. The code is flagged as an unspecified code, since codes identifying laterality exist in the same family. Coders also document this condition as corneal allograft rejection. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Complication of transplanted organs or tissue, initial encounter.

Code Identity

ICD-10-CM Code
T86.8409
Billable Status
Yes — Valid for Submission
Code Describes
Corneal transplant rejection, unspecified eye
Short Description
Corneal transplant rejection, unspecified eye
Same as the full description in the CMS dataset.
Parent Code
T86.840
Corneal transplant rejection

Code Classification

ChapterS00–T88Injury, poisoning and certain other consequences of external causes
SectionT80-T88Complications of surgical and medical care, not elsewhere classified
CategoryT86Complications of transplanted organs and tissue
This CodeT86.8409Corneal transplant rejection, unspecified eye

Code EditsBilling

Medicare Code Editor checks that affect claim validity for T86.8409.

Unspecified codes
Unspecified codes exist in the ICD-10-CM classification for circumstances when documentation in the medical record does not provide the level of detail needed to support reporting a more specific code. However, in the inpatient setting, there should generally be very limited and rare circumstances for which the laterality (right, left, bilateral) of a condition is unable to be documented and reported. The following pages contain the list of unspecified ICD-10-CM diagnosis codes for which there is a more specific code to identify laterality (right, left, bilateral) within that code family.

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Corneal allograft rejection
  • Corneal endothelial allograft rejection
  • Corneal epithelial allograft rejection
  • Corneal graft rejection
  • Corneal subepithelial allograft rejection
  • Graft rejection line
  • Rejection of corneal graft after penetrating keratoplasty

Coding GuidelinesGuidance

The appropriate 7th character is to be added to each code from block Complications of transplanted organs and tissue (T86). Use the following options for the applicable episode of care:

  • A - initial encounter
  • D - subsequent encounter
  • S - sequela

Source: ICD-10-CM Official Guidelines for Coding and Reporting, FY 2026, published by CMS and the National Center for Health Statistics.

Clinical ClassificationClinical

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

CCSR INJ036
Complication of transplanted organs or tissue, initial encounter
Default principal diagnosis: inpatient Yes · outpatient Yes

Code History & ChangesHistory

Replacement T86.8409 replaces the following previously assigned code(s):

  • T86.840 - Corneal transplant rejection
FY 2021AddedAdded to the ICD-10-CM code setEffective October 1, 2020.
FY 2022–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About T86.8409Overview

Is T86.8409 (Corneal transplant rejection) a billable code?

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

What MS-DRG does T86.8409 group to?

When corneal transplant rejection, unspecified eye is the principal diagnosis on an inpatient stay, it groups to MS-DRG 124, 125, with relative weights from 0.7678 to 1.3231 depending on complications. Higher weights mean higher Medicare reimbursement.

Footnotes

[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:

  • The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
  • The condition places limitations on self-care, independent living, and social interactions.