Cytokine release syndrome, grade 3

This code represents a severe systemic inflammatory response characterized by widespread cytokine activation, leading to significant organ dysfunction. It is often a serious complication of immunotherapies, such as CAR T-cell therapy, or other immune-modulating treatments. Grade 3 indicates a life-threatening condition requiring urgent intervention.

Use this code when documentation explicitly states "cytokine release syndrome, grade 3" or describes a severe, life-threatening CRS event with corresponding clinical findings (e.g., severe hypoxia, significant vasopressor requirement, grade 3 neurological toxicity). This code is typically assigned when the patient is receiving treatment for an underlying malignancy or autoimmune disorder with an immunotherapy known to cause CRS.

• Ensure the medical record clearly specifies "grade 3" CRS; do not assume the grade based on treatment alone.
• Always code the underlying condition (e.g., malignancy) first, as CRS is a complication of treatment for that condition.
• Differentiate from other systemic inflammatory responses like sepsis, which has a different etiology and coding pathway.