ICD-10 Code D89.833 – Cytokine release syndrome, grade 3 (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code D89.833 – Cytokine release syndrome, grade 3
What it is
D89.833 identifies cytokine release syndrome graded as severe, meaning the inflammatory reaction is more than mild or moderate. Use it when documentation specifically states grade 3 cytokine release syndrome.
Clinical signs
Clinical features vary; refer to documentation. Grade 3 cases generally reflect significant systemic inflammation with marked symptoms that require urgent medical attention and closer monitoring.
When to use this code
Use this code when the clinician documents cytokine release syndrome and clearly assigns grade 3. It may appear after immunotherapy, cellular therapy, or other immune-triggering treatment, but only code it when the grade is stated. If the record describes CRS without a grade, check documentation.
Do not use for
Do not use D89.833 for ungraded cytokine release syndrome or for other inflammatory reactions that are not documented as CRS. Do not assume grade 3 from severity alone.
Coding tip
Code the documented grade exactly as written and query the provider if the grade is missing or unclear.