Tryptase

Tryptase (mast cell tryptase) is a protease (enzyme that can cleave proteins) stored and released by mast cells in the granules. Tryptase is released into the circulation along with histamine during abrupt mast cell degranulation, as occurs in anaphylactic and anaphylactoid reactions (anaphylaxis). Mast cells are thus the primary effector cells of the allergic reaction.

Thus, tryptase can be seen as a marker of allergic reactions. Tryptase is detectable longer than the other markers histamine or leukotrienes, prostaglandins, etc.

The procedure

Material required

  • Blood serum
  • A sample shipment should be refrigerated (2-8 °C).

Preparation of the patient

Interfering factors

  • Not known

Normal value – blood serum

Reference range in μg/l < 13,5

Indications

  • Allergy diagnostics (including insect venom allergy/venom allergy).
  • Anaphylactic shock
  • Mastocytosis – rare disorder characterized by accumulations of mast cells in the skin (cutaneous mastocytosis) or internal organs/bone marrow (systemic mastocytosis).

Interpretation

Interpretation of increased values

  • Allergy diagnosis (values 12-20 μg/l indicate excessive mast cell presence).
  • Anaphylactic shock (values 20-200 μg/l; decrease to normal within 24-48 hours).
  • Mastocytosis (values 20- > 1,000 μg/l) – greatly increased occurrence of mast cells in the skin and/or organs.

Interpretation of lowered values

  • Not relevant to the disease

Further notes

  • People with elevated tryptase levels (4-6% of the population) are prone to urticaria (hives; skin with wheals, redness, and itching). Furthermore, when they sit up after lying down, they may experience palpitations (“postural tachycardia syndrome”); some even faint. Some suffer from irritable bowel syndrome (IBS). They react to insect bites more violently than other people.