Elevated total serum tryptase

What it means

An abnormally elevated concentration of total tryptase (alpha and beta tryptase) in the blood circulation.

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.

Rare diseases that can present with this8

The range is how often this sign appears among people diagnosed with each disease — it is not a probability of having any of them. Many of these signs also occur in common, non-rare conditions. A sign on this page is a conversation to have with a clinician, not a conclusion.

Part of the broader category