Abnormal circulating enzyme concentration or activity Elevated total serum tryptase 2018-05-19T15:17:36Z Tryptase is a serine protease that is primarily produced and stored in mast cells (MCs) and less abundantly in blood basophils [31-34]. In tissue MCs, tryptase is produced and released in a constitutive manner, regardless of the organ, location of MCs, maturation stage or subtype of MCs. Mature tissue MCs also store larger quantities of the enzyme in their metachromatic granules. Two major forms of tryptase are produced in MCs, alpha-tryptase and beta-tryptase. Whereas the alpha form is produced and released constantly in MCs, the beta-form is primarily stored in MC granules. During an anaphylactic reaction, MCs rapidly release substantial amounts of alpha- and beta tryptases. Current tests measure total tryptase (alpha and beta), not differentiating between these isoforms. The presence of elevated tryptase may occur acutely due to mast cell degranulation. Alternatively, chronic elevation of basal serum tryptase may be present in individuals with: 1) clonal myeloid neoplasms; 2) the genetic trait hereditary alpha-tryptasemia; 3) chronic kidney disease. Serum tryptase levels are useful in the diagnosis of mast cell activation, clonal myeloid disease, and hereditary alpha-tryptasemia. HP:0031900 An abnormally elevated concentration of total tryptase (alpha and beta tryptase) in the blood circulation.