CRS grade represents the severity of Cytokine Release Syndrome (CRS), a systemic inflammatory response that can occur following certain immunotherapies. The CRS grade is determined by the more severe event: hypotension or hypoxia not attributable to any other cause. In essence, the grade reflects the highest level of severity observed for either hypotension or hypoxia.
For example, a patient exhibiting a temperature of 39.5°C, hypotension requiring one vasopressor, and hypoxia requiring low-flow nasal cannula is classified as grade 3 CRS. This classification is based on the severity of hypotension or hypoxia, not on the fever alone.
