2027 ICD-10-CM Diagnosis Code T86.5Complications of stem cell transplant

ICD-10-CM Codes›S00–T88›T80-T88›T86

ICD-10-CM T86.5
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

T86.5 is a billable ICD-10-CM diagnosis code for complications of stem cell transplant. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 919 through 921. As a secondary diagnosis, it counts as a complication or comorbidity (CC) and moves an inpatient stay to a higher severity level within its MS-DRG family. It does not count, however, when the principal diagnosis is one of 48 closely related codes. Coders also document this condition as bronchiolitis obliterans syndrome following allogeneic stem cell transplant. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Complication of transplanted organs or tissue, initial encounter.

For Medicare Advantage risk adjustment, T86.5 maps to CMS-HCC Category 454 (Stem Cell, Including Bone Marrow, Transplant Status/Complications) under the V28 model, adding a risk factor of about 1.068 for a community, non-dual, aged beneficiary in payment year 2027.

Code Identity

ICD-10-CM Code
T86.5
Billable Status
Yes — Valid for Submission
Code Describes
Complications of stem cell transplant
Short Description
Complications of stem cell transplant
Same as the full description in the CMS dataset.
Parent Code
T86
Complications of transplanted organs and tissue

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 CodeT86.5Complications of stem cell transplant

Medicare Risk Adjustment (HCC)Billing

T86.5 maps to a payment category in the CMS-HCC model used to risk-adjust Medicare Advantage payments. Weights are the published community factors for payment year 2027.

CMS-HCC V28 Category (Payment Model)
HCC 454— Stem Cell, Including Bone Marrow, Transplant Status/Complications
Payment HCC · PY 2027 one of 14 ICD-10-CM codes in this category
Risk Adjustment Factor (RAF) Weight
+1.068
community, non-dual, aged · ranges 0.416–1.596 across segments
Hierarchy
Top of its hierarchy
HCC 454 is not superseded by any other condition category
Prior Model (CMS-HCC V24)
HCC 186
V24 retired V28 pays 100% of MA risk scores since PY 2026
Other CMS Models
PACE (CMS-HCC V22): HCC 186 · ESRD (V21): HCC 186 · ESRD (V24): HCC 186
ESRD V21 weights: 0.154 dialysis, 0.075 functioning graft · ESRD V24 weights: 0.138 dialysis, 0.000 functioning graft
Part D (RxHCC)
RxHCC 395 — Stem Cell, Including Bone Marrow, Transplant Status/Complications
also risk-adjusts in the Part D prescription drug model (V08)

Source: CMS Payment Year 2027 risk adjustment mappings and model software. Weights are relative factors, not dollar amounts; a beneficiary's total RAF also includes demographics and interactions. Browse all CMS-HCC categories.

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Bronchiolitis obliterans syndrome following allogeneic stem cell transplant
  • Chronic bronchiolitis
  • Chronic graft-versus-host disease
  • Chronic obliterative bronchiolitis
  • Disorder due to and following transplantation of stem cell
  • Thrombotic microangiopathy following transplantation of hematopoietic stem cell

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 2027, published by CMS and the National Center for Health Statistics.

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to T86.5: its own notes plus those printed at T86, block T80-T88, and Chapter 19. A note printed at a category, block or chapter applies to every code under it.

Applicable To

Conditions this code is used for: synonyms of the title or, for "other specified" codes, the conditions assigned to it. The list is not exhaustive.

  • Complications from stem cells from peripheral blood
  • Complications from stem cells from umbilical cord

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 Block T80-T88 Complications of surgical and medical care, not elsewhere classified applies to 1,683 codes
  • any encounters with medical care for postprocedural conditions in which no complications are present, such as:
  • artificial opening status (Z93.-)
  • closure of external stoma (Z43.-)
  • fitting and adjustment of external prosthetic device (Z44.-)
  • burns and corrosions from local applications and irradiation (T20-T32)
  • complications of surgical procedures during pregnancy, childbirth and the puerperium (O00-O9A)
  • mechanical complication of respirator [ventilator] (J95.850)
  • poisoning and toxic effects of drugs and chemicals (T36-T65 with fifth or sixth character 1-4 or 6)
  • postprocedural fever (R50.82)
  • specified complications classified elsewhere, such as:
  • cerebrospinal fluid leak from spinal puncture (G97.0)
  • colostomy malfunction (K94.0-)
  • disorders of fluid and electrolyte imbalance (E86-E87)
  • functional disturbances following cardiac surgery (I97.0-I97.1)
  • intraoperative and postprocedural complications of specified body systems (D78.-, E36.-, E89.-, G97.3-, G97.4, H59.3-, H59.-, H95.2-, H95.3, I97.4-, I97.5, J95.6-, J95.7, K91.6-, L76.-, M96.-, N99.-)
  • ostomy complications (J95.0-, K94.-, N99.5-)
  • postgastric surgery syndromes (K91.1)
  • postlaminectomy syndrome NEC (M96.1)
  • postmastectomy lymphedema syndrome (I97.2)
  • postsurgical blind-loop syndrome (K91.2)
  • ventilator associated pneumonia (J95.851)
From Chapter 19 (S00-T88) Injury, poisoning and certain other consequences of external causes applies to 41,187 codes

Use Additional Code

Add a second code, after this one, to fully describe the condition.

From T86 Complications of transplanted organs and tissue applies to 77 codes
  • code to identify other transplant complications, such as:
  • graft-versus-host disease (D89.81-)
  • malignancy associated with organ transplant (C80.2)
  • post-transplant lymphoproliferative disorders (PTLD) (D47.Z1)
From Block T80-T88 Complications of surgical and medical care, not elsewhere classified applies to 1,683 codes
  • code for adverse effect, if applicable, to identify drug (T36-T50 with fifth or sixth character 5)
  • code(s) to identify the specified condition resulting from the complication
  • code to identify devices involved and details of circumstances (Y62-Y82)
From Chapter 19 (S00-T88) Injury, poisoning and certain other consequences of external causes applies to 41,187 codes
  • code to identify any retained foreign body, if applicable (Z18.-)

Notes

General instructions on how these codes are used.

From Chapter 19 (S00-T88) Injury, poisoning and certain other consequences of external causes applies to 41,187 codes
  • Use secondary code(s) from Chapter 20, External causes of morbidity, to indicate cause of injury. Codes within the T section that include the external cause do not require an additional external cause code
  • The chapter uses the S-section for coding different types of injuries related to single body regions and the T-section to cover injuries to unspecified body regions as well as poisoning and certain other consequences of external causes.

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

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name T86.5, its category, or a range that includes it.

Excludes1 1

These codes carry an Excludes1 note naming T86.5: they are not reported together with it, unless the two conditions are unrelated.

  • Z98.85 Transplanted organ removal status
    encounter for removal of transplanted organ -code to complication of transplanted organ (T86.-) names T86.-, which includes this code

Excludes2 7

These codes carry an Excludes2 note naming T86.5: its condition is not part of those codes, and both may be reported when the patient has both.

  • T80.82 Complication of immune effector cellular therapy
    complication of stem cell transplant (T86.5)
  • D89 Other disorders involving the immune mechanism, not elsewhere classified
    transplant failure and rejection (T86.-) names T86.-, which includes this code
  • T81 Complications of procedures, not elsewhere classified
    complications of transplanted organs and tissue (T86.-) names T86.-, which includes this code
  • T82 Complications of cardiac and vascular prosthetic devices, implants and grafts
    failure and rejection of transplanted organs and tissue (T86.-) names T86.-, which includes this code
  • T83 Complications of genitourinary prosthetic devices, implants and grafts
    failure and rejection of transplanted organs and tissue (T86.-) names T86.-, which includes this code
  • T84 Complications of internal orthopedic prosthetic devices, implants and grafts
    failure and rejection of transplanted organs and tissues (T86.-) names T86.-, which includes this code
  • T85 Complications of other internal prosthetic devices, implants and grafts
    failure and rejection of transplanted organs and tissue (T86.-) names T86.-, which includes this code

Code First 6

These codes say to code first a condition named in the note, and T86.5 is one of the conditions named.

  • J44.81 Bronchiolitis obliterans and bronchiolitis obliterans syndrome
    complication of stem cell transplant (T86.5)
  • M31.11 Hematopoietic stem cell transplantation-associated thrombotic microangiopathy [HSCT-TMA]
    complications of stem cell transplant (T86.5)
  • C80.2 Malignant neoplasm associated with transplanted organ
    complication of transplanted organ (T86.-) names T86.-, which includes this code
  • D47.Z1 Post-transplant lymphoproliferative disorder (PTLD)
    complications of transplanted organs and tissue (T86.-) names T86.-, which includes this code
  • D89.81 Graft-versus-host disease
    complications of transplanted organs and tissue (T86.-) names T86.-, which includes this code
  • D89.83 Cytokine release syndrome
    complications of transplanted organs and tissue (T86.-) names T86.-, which includes this code

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

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

Convert T86.5 to ICD-9-CMHistory

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

ICD-9-CM
996.88 Comp tp organ-stem cell
Exact Match The mapping is direct, with no qualifiers.

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 T86.5Overview

What is the ICD-10 code for complications of stem cell transplant?

The ICD-10-CM code for complications of stem cell transplant is T86.5 (sometimes written as T865). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is T86.5 (Complications of transplanted organs and tissue) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report complications of stem cell transplant on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does T86.5 group to?

When complications of stem cell transplant is the principal diagnosis on an inpatient stay, it groups to MS-DRG 920, 919, 921, with relative weights from 0.6719 to 1.7624 depending on complications. Higher weights mean higher Medicare reimbursement.

Is T86.5 a CC or MCC?

CMS lists T86.5 as a CC (complication or comorbidity) for FY 2027. Reported as a secondary diagnosis, it moves the inpatient stay to a higher-weighted DRG within its severity family. It does not count when the principal diagnosis is one of the 48 closely related codes in its exclusion list.

Does T86.5 need an additional code?

When the condition applies, yes. The Use Additional Code note at T86, which applies to T86.5, reads: code to identify other transplant complications, such as: graft-versus-host disease (D89.81-); malignancy associated with organ transplant (C80.2); post-transplant lymphoproliferative disorders (PTLD) (D47.Z1). The additional code is reported after T86.5.

What HCC is T86.5?

T86.5 (complications of stem cell transplant) maps to CMS-HCC Category 454 (Stem Cell, Including Bone Marrow, Transplant Status/Complications), commonly written as HCC 454, in the CMS-HCC V28 model used for Medicare Advantage risk adjustment in payment year 2027. It mapped to HCC 186 under the retired V24 model. It also maps in the PACE (CMS-HCC V22), ESRD (V21), and ESRD (V24) models. In the Part D prescription drug model it maps to RxHCC 395.

Does T86.5 risk-adjust for Medicare Advantage payment?

Yes. When documented and reported on a Medicare Advantage encounter, T86.5 adds a risk adjustment factor of about 1.068 to the beneficiary's RAF score for a community, non-dual, aged enrollee (published V28 weights range from 0.416 to 1.596 depending on the payment segment). HCC 454 sits at the top of its hierarchy, so no other condition category supersedes it. See the full factor table on the HCC 454 category page.