Serum tryptase measurement is used to assess mast cell activation, which may result from anaphylaxis or allergy, and to evaluate patients with systemic mastocytosis or mast cell activation syndrome.
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Tryptase is the most abundant protein component of mast cell secretory granules. Serum tryptase levels generally reflect the extent of mast cell activation, either through IgE or non-IgE-mediated mechanisms. Basophils also produce small amounts of tryptase.
Measurement of serum tryptase is often part of the diagnostic evaluation of a patient with suspected mastocytosis (cutaneous or systemic). Serum tryptase levels appear to correlate with mast cell activation in these patients. Mastocytosis (or mastocytosis) should be considered in the differential diagnosis of patients presenting with severe allergic reactions without a specific and recognized allergic stimulus. Systemic mastocytosis may cause symptoms such as peptic ulceration, chronic diarrhea, and joint pain. These patients may have hepatomegaly, splenomegaly, or lymphadenopathy. There may also be skin involvement with rashes or characteristic red vesicular lesions.
Tryptase measurement may help confirm anaphylaxis as the cause of a patient's acute symptoms, especially when the diagnosis is unclear and/or the symptoms are recurrent. In anaphylaxis, tryptase levels peak approximately one to two hours after the onset of symptoms and then decline slowly over the next three to six hours. The biological half-life of tryptase is approximately 2 hours.
Systemic mastocytosis is a risk factor for anaphylactic reactions, particularly in response to drugs and insect stings. Patients with elevated normal serum tryptase levels may be at increased risk for severe anaphylactic reactions. The risk associated with elevated tryptase levels is more significant in individuals with a history of severe systemic reactions. Transiently elevated tryptase levels during a severe reaction to an allergen, such as insect venom or a drug, suggest that mast cell activation may play a role in the response.
Abnormally elevated tryptase levels reflect mast cell activation in certain hematologic disorders and neoplasms, whether or not there is established systemic mastocytosis. Hematologic disorders involving the uncontrolled growth of immature myeloid cells in the bone marrow and/or bloodstream may be accompanied by elevated serum tryptase levels.
Possible Interpretations of Pathological Values
- Increase: Tryptase values greater than 11.50 ng/mL are indicative of mast cell activation as a result of anaphylaxis or due to an increase in mast cell numbers (e.g., patients with mastocytosis)
- Decrease: Values below 0.40 ng/ml are clinically meaningless.
Important Note
Laboratory test results are the most critical parameter for diagnosing and monitoring all pathological conditions. Between 70 to 80% of diagnostic decisions are based on laboratory tests. Correctly interpreting laboratory results allows a doctor to distinguish "healthy" from "diseased."
Laboratory test results should not be interpreted from the numerical result of a single analysis. Test results should be analyzed based on each case and family history, clinical findings, and the results of other laboratory tests and information. Your physician should explain the importance of your test results.
At Diagnostiki Athinon, we answer any questions you may have about the test you perform in our laboratory and contact your doctor to ensure you receive the best possible medical care.
