2026 ICD-10-CM Diagnosis Code D89.835Cytokine release syndrome, grade 5

ICD-10-CM Codes›D50–D89›D80-D89›D89

ICD-10-CM D89.835
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

D89.835 is a billable ICD-10-CM diagnosis code for cytokine release syndrome, grade 5. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 814 through 816. The code is not accepted as a principal diagnosis by the Medicare Code Editor. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Immunity disorders.

Code Identity

ICD-10-CM Code
D89.835
Billable Status
Yes — Valid for Submission
Code Describes
Cytokine release syndrome, grade 5
Short Description
Cytokine release syndrome, grade 5
Same as the full description in the CMS dataset.
Parent Code
D89.83
Cytokine release syndrome

Code Classification

ChapterD50–D89Diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism
SectionD80-D89Certain disorders involving the immune mechanism
CategoryD89Other disorders involving the immune mechanism, not elsewhere classified
This CodeD89.835Cytokine release syndrome, grade 5

Code EditsBilling

Medicare Code Editor checks that affect claim validity for D89.835.

Unacceptable principal diagnosis
There are selected codes that describe a circumstance which influences an individual's health status but not a current illness or injury, or codes that are not specific manifestations but may be due to an underlying cause. These codes are considered unacceptable as a principal diagnosis.

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 BLD008
Immunity disorders
Default principal diagnosis: inpatient No · outpatient Yes

Clinical InformationClinical

  • Cytokine Release Syndrome

    a severe immune reaction characterized by excessive release of cytokines. symptoms include dyspnea; fever; headache; hypotension; nausea; rash; tachycardia; hypoxia; hyperferritinemia, and multiple organ failure. it is associated with viral infections, sepsis; autoimmune diseases and a variety of factors used in immunotherapy.

Code History & ChangesHistory

Replacement D89.835 replaces the following previously assigned code(s):

  • D89.89 - Oth disrd involving the immune mechanism, NEC
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 D89.835Overview

What is the ICD-10 code for cytokine release syndrome, grade 5?

The ICD-10-CM code for cytokine release syndrome, grade 5 is D89.835 (sometimes written as D89835). It is billable on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

Is D89.835 (Cytokine release syndrome) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report cytokine release syndrome, grade 5 on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does D89.835 group to?

On inpatient claims, cytokine release syndrome, grade 5 maps to MS-DRG 814, 815, 816, with relative weights from 0.6320 to 2.1267 depending on complications. Higher weights mean higher Medicare reimbursement.

Can D89.835 be a principal diagnosis?

No. The Medicare Code Editor rejects this code as a principal diagnosis because cytokine release syndrome, grade 5 describes a circumstance that influences health status rather than a current illness. Report it as a secondary diagnosis.