Table 8. CTCAE Grading for Infusion-Related Reactions, Cytokine Release Syndrome, and Anaphylaxis.

CTCAE term	Grade 1	Grade 2	Grade 3	Grade 4	Grade 5
Infusion-related reactiona	Mild transient reaction; infusion interruption not indicated; intervention not indicated	Therapy or infusion interruption indicated but responds promptly to symptomatic treatment (e.g., antihistamines, NSAIDS, narcotics, IV fluids); prophylactic medications indicated for ≤ 24 hr	Prolonged (e.g., not rapidly responsive to symptomatic medication and/or brief interruption of infusion); recurrence of symptoms following initial improvement; hospitalization indicated for clinical sequelae	Life-threatening consequences; urgent intervention indicated	Death
Cytokine release syndromeb	Fever with or without constitutional symptoms	Hypotension responding to fluids; hypoxia responding to < 40% O2	Hypotension managed with one pressor; hypoxia requiring ≥ 40% O2	Life-threatening consequences; urgent intervention indicated	Death
Anaphylaxisc			Symptomatic bronchospasm, with or without urticaria; parenteral intervention indicated; allergy-related edema/angioedema; hypotension	Life-threatening consequences; urgent intervention indicated	Death

Note. CTCAE = Common Terminology Criteria for Adverse Events; NSAID = nonsteroidal anti-inflammatory drug. Information from National Institutes of Health (2017).

^aInfusion-related reaction is a disorder characterized by adverse reaction to the infusion of pharmacological or biological substances.

^bCytokine release syndrome is characterized by fever, tachypnea, headache, tachycardia, hypotension, rash, and/or hypoxia caused by the release of cytokines.

^cAnaphylaxis is characterized by an acute inflammatory reaction resulting from the release of histamine and histamine-like substances from mast cells, causing a hypersensitivity immune response. Clinically, it presents with breathing difficulty, dizziness, hypotension, cyanosis, and loss of consciousness, and may lead to death.