Serum tryptase measurement is used to evaluate mast cell activation, which may be the result of anaphylaxis or allergy, as well as to evaluate patients with systemic mast cell activation or mast cell activation syndrome.
Tryptase is the most abundant protein component of the secretory mast cells. Serum tryptase levels generally reflect the extent of mast cell activation, either through IgE mechanisms or through non-IgE-mediated mechanisms. Basophils also produce small amounts of tryptase.
Measurement of tryptase in serum is often part of the diagnostic evaluation of a patient with suspected mast cell (skin or systemic) disease. Serum tryptase levels appear to correlate with mast cell activation in these patients. Mastocytosis should be taken into account during the differential diagnosis of patients experiencing severe allergic reactions without any specific and recognized allergic stimuli. Systemic mastocytosis can cause symptoms such as peptic ulcer, chronic diarrhea and joint pain. These patients may have hepatomegaly, splenomegaly, or lymph node swelling. There may be skin involvement with rashes or characteristic red bubble lesions.
Measurement of tryptase can help confirm anaphylaxis as a cause of a patient's acute symptoms, especially when the diagnosis is unclear and / or the symptoms are recurrent. In anaphylaxis, tryptase levels peak at about 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 mast cell lysis is a risk factor for anaphylactic reactions, particularly in response to drugs and insect bites. Patients with elevated normal serum tryptase levels may be at increased risk for severe anaphylactic reactions. The risk associated with elevated tryptase levels is greater in people with a history of severe systemic reactions. Transiently elevated tryptase levels during a severe reaction to an allergen, such as insect poisons or a drug, suggest that mast cell activation may play a role in triggering the reaction.
Abnormally elevated tryptase levels reflect mast cell activation in certain hematological abnormalities and neoplasms, whether or not systemic mast cells are established. Hematological disorders, including the uncontrolled development of immature marrow cells in the bone marrow and / or the 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 count (eg patients with mast cell infiltration)
- Decrease: Values below 0.40 ng / ml are clinically meaningless.
Laboratory test results are the most important parameter for the diagnosis and monitoring of all pathological conditions. 70%-80% of diagnostic decisions are based on laboratory tests. Correct interpretation of 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 interpreted in relation to each individual case and family history, clinical findings and the results of other laboratory tests and information. Your personal physician should explain the importance of your test results.
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