Tryptase in Serum

Tryptase in serum is a laboratory test that measures the level of tryptase, an enzyme found in mast cells. These cells play a key role in immune responses, including allergies and inflammatory processes. The test is mainly used to assess suspected mastocytosis — a rare condition in which abnormal mast cells accumulate in the skin or internal organs.

🧭 When is the test ordered?

Tryptase testing is recommended in the following situations:

• recurrent symptoms of anaphylaxis (including shock, fainting, or hypotension);
• unexplained skin rashes accompanied by itching, swelling, and redness;
• suspected mastocytosis — either cutaneous or systemic forms;
• persistently elevated tryptase levels combined with signs of mast cell activation (such as abdominal pain, diarrhea, hot flashes, bone pain, fatigue).

🔍 What levels are considered healthy?

• Normal tryptase is usually <11.4 ng/mL.
• Elevated levels >20 ng/mL may indicate systemic mastocytosis, especially if other diagnostic criteria are met.

Tryptase levels typically peak within 1–2 hours after the onset of an anaphylactic reaction and return to normal within 6–24 hours.

Important: High tryptase alone is not a diagnosis, but it is considered a minor criterion in the WHO classification for systemic mastocytosis.

🧩 If tryptase levels are elevated

A repeat test may be recommended, especially if symptoms are present.

Additional evaluations may include:

• KIT gene mutation testing (D816V);
• bone marrow biopsy (to rule out systemic mastocytosis);
• urine analysis for histamine metabolites (e.g., methylhistamine);
• abdominal ultrasound;
• bone density testing (due to the risk of osteopenia and osteoporosis).

Antihistamines should be stopped 24 hours before testing, if possible and in consultation with your physician, to avoid inaccurate results.

📌 Additional information

Mastocytosis presents in many ways — from heat-reactive skin spots to severe systemic symptoms. Some patients may have persistently elevated tryptase without symptoms, while others experience significant issues even with moderate levels. This highlights the importance of comprehensive evaluation.