2026 ICD-10-CM Diagnosis Code T86.01Bone marrow transplant rejection

ICD-10-CM Codes›S00–T88›T80-T88›T86

ICD-10-CM T86.01
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

T86.01 is a billable ICD-10-CM diagnosis code for bone marrow transplant rejection. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 808 through 810. 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
T86.01
Billable Status
Yes — Valid for Submission
Code Describes
Bone marrow transplant rejection
Short Description
Bone marrow transplant rejection
Same as the full description in the CMS dataset.
Parent Code
T86.0
Complications of bone marrow transplant

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 CodeT86.01Bone marrow transplant rejection

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Accelerated rejection of bone marrow transplant
  • Acute rejection of bone marrow transplant
  • Bone marrow transplant present
  • Bone marrow transplant rejection
  • Chronic rejection of bone marrow transplant
  • Disorder of transplanted bone marrow
  • Hyperacute rejection of bone marrow transplant

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.

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Complication(s) (from) (of)
      • transplant
        • bone marrow
          • rejection
    • Rejection
      • transplant
        • bone
          • marrow

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

Patient EducationClinical

Bone Marrow Transplantation

Bone marrow is the spongy tissue inside some of your bones, such as your hip and thigh bones. It contains immature cells, called stem cells. The stem cells can develop into red blood cells, which carry oxygen throughout the body, white blood cells, which fight infections, and platelets, which help the blood to clot.

Read the full article at MedlinePlus

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

Convert T86.01 to ICD-9-CMHistory

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

ICD-9-CM
996.85 Compl marrow transplant
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 T86.01Overview

Is T86.01 (Complications of bone marrow transplant) a billable code?

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

What MS-DRG does T86.01 group to?

When bone marrow transplant rejection is the principal diagnosis on an inpatient stay, it groups to MS-DRG 808, 809, 810, with relative weights from 1.0466 to 2.2079 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of T86.01?

Under the General Equivalence Mappings, bone marrow transplant rejection converts to ICD-9-CM 996.85 (compl marrow transplant). The mapping is approximate, so confirm the match fits the documentation.

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.