An increase in serum tryptase even below 11.4 ng/mL may indicate a mast cell‐mediated hypersensitivity reaction: a prospective study in <scp>H</scp>ymenoptera venom allergic patients

Serum tryptase values obtained during a suspected hypersensitivity reaction must always be compared to a baseline value. A relative tryptase increase to ≥135% of the baseline value during a suspected hypersensitivity reaction indicates mast cell activation even below 11.4 ng/mL.