Tryptase

Tryptase is the most abundant secretory granule-derived serine proteinase contained in mast cells that has recently been used as a marker for mast cell activation. It is involved with allergenic response and is suspected to act as a mitogen for fibroblast lines. Elevated levels of serum tryptase occur in both anaphylactic and anaphylactoid reactions, but a negative test does not exclude anaphylaxis.