Mature and total tryptase levels in anaphylaxis, systemic mastocytosis, and alpha-tryptasemia

* Reference ranges may vary slightly among different laboratories.
¶ Level related to clinical severity (hypotension), timing of sample collection in relation to onset of signs and symptoms, and nature of the anaphylactic stimulus.
Δ Reflects primarily the total body burden of mast cells when subject is in a nonanaphylactic state. A baseline total tryptase level >11.4 ng/mL should raise the possibility of an underlying clonal mast cell disorder (eg, systemic mastocytosis), particularly in a subject with a history of systemic anaphylaxis or a primary mast cell activation disorder.
◊ Reflects increased TPSAB1 gene copy number when that gene encodes alpha-tryptase, leading to increased formation of alpha/beta-tryptase heterotetramers, which in turn may account for severe episodes of spontaneous or allergen-triggered systemic anaphylaxis.