Cytokine release syndrome, grade 1

This code signifies a mild systemic inflammatory response characterized by constitutional symptoms such as fever, fatigue, and headache, often accompanied by laboratory abnormalities like elevated inflammatory markers. It represents the lowest severity of cytokine release syndrome (CRS), a potentially life-threatening condition resulting from an overwhelming immune response.

Use this code when documentation explicitly states "cytokine release syndrome, grade 1" or when clinical indicators align with grade 1 CRS following immunotherapy, such as CAR T-cell therapy or bispecific antibodies. Supporting documentation should detail the patient's symptoms and laboratory findings consistent with the lowest severity grading of CRS.

• Ensure the physician's documentation clearly specifies the grade of CRS.
• Do not use this code for other types of systemic inflammatory response syndrome (SIRS) unless CRS is explicitly diagnosed.
• Consider sequencing this code after the underlying condition or treatment that precipitated the CRS, if applicable.