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HelpTest Code TRYPT Tryptase, Serum
Reporting Name
Tryptase, SUseful For
Evaluation of individuals with suspected mast cell activation, which may occur as a result of anaphylaxis or allergen challenge
Evaluation of patients with suspected cutaneous or systemic mastocytosis
Testing Algorithm
For more information, see Mast Cell Disorder: Diagnostic Algorithm, Bone Marrow
Method Name
Fluorescence Enzyme Immunoassay (FEIA)
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Specimen Type
SerumSpecimen Required
Collection Container/Tube:
Preferred: Serum gel
Acceptable: Red top
Submission Container/Tube: Plastic vial
Specimen Volume: 0.5 mL
Collection Instructions: Centrifuge and aliquot serum into plastic vial
Additional Information: Tryptase degenerates very quickly when left in the presence of red blood cells.
Specimen Minimum Volume
0.2 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Serum | Frozen (preferred) | 14 days | |
| Refrigerated | 7 days |
Reject Due To
| Gross hemolysis | OK |
| Gross lipemia | OK |
| Gross icterus | OK |
Special Instructions
Reference Values
<11.5 ng/mL
Day(s) Performed
Monday through Friday
CPT Code Information
83520
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| TRYPT | Tryptase, S | 21582-2 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| TRYPT | Tryptase, S | 21582-2 |
Clinical Information
Tryptase, a neutral protease, is a dominant protein component of the secretory granules of human mast cells. There are 2 forms of tryptase, designated as alpha and beta, which are encoded by 2 separate genes.(1) Both are expressed as inactive proenzymes. Alpha-protryptase and beta-protryptase are spontaneously released from resting mast cells. The levels of the protrypases reflect the total number of mass cells within the body but are not an indication of mast cell activation. Beta-protryptase is processed to a mature form, which is stored in granules and released as an active tetramer that is bound to heparan or chondroitin sulfate proteoglycans. In contrast, an amino acid change in alpha-protryptase prevents processing to a mature form. Upon mast cell activation, degranulation releases mature tryptase, which is almost exclusively in the form of beta-tryptase.
During an anaphylactic episode, mast cell granules release tryptase; measurable amounts are found in blood, generally within 30 to 60 minutes.(2) The levels decline under first-order kinetics with half-life of approximately 2 hours. Measurement of tryptase 1 to 6 hours and at least 24 hours after the anaphylactic episode may be useful in demonstrating a return to baseline concentrations and evaluating the kinetics of the response. Tryptase concentrations may also be increased for a period of time following allergen challenge.
Mastocytosis occurs when there is clonal mast-cell proliferation, which leads to tissue accumulation.(3) Mastocytosis can be categorized as cutaneous and systemic. Cutaneous mastocytosis is generally associated with normal or slightly elevated (11.5-20.0 ng/mL) concentrations of tryptase. In systemic mastocytosis, high concentrations may be observed, with greater than 20 ng/mL being a minor criterion for the diagnosis of this condition.
Interpretation
Transient tryptase concentrations greater than or equal to 11.5 ng/mL may be consistent with mast cell activation in the context of anaphylaxis or allergen challenge; measurement of tryptase in specimens obtained 1 to 6 hours and at least 24 hours after the episode may be useful in demonstrating a return to baseline concentrations.
Basal tryptase concentrations greater than or equal to 11.5 mg/mL may be consistent with cutaneous mastocytosis.
Basal tryptase concentrations greater than or equal to 20 ng/mL may be consistent with systemic mastocytosis.
Cautions
Normal tryptase concentrations may be observed in some patients with acute mast cell activation if specimens are obtained greater than 12 hours after an anaphylactic episode or allergen challenge.
Some individuals may demonstrate an increase in tryptase concentrations above baseline after anaphylaxis or allergen challenge while remaining below 11.5 ng/mL; measurement of tryptase in specimens obtained 1 to 6 hours and at least 24 hours after the episode may be useful in demonstrating a transient increase in concentrations.
Method Description
Anti-tryptase, covalently coupled to ImmunoCAP, reacts with tryptase in the patient serum specimen. After washing, enzyme-labeled antibodies against tryptase are added to form a complex. After incubation, unbound enzyme-labeled antibodies are washed away, and the bound complex is incubated with a developing agent. After stopping the reaction, the fluorescence in the eluate is measured. The fluorescence is directly proportional to the concentration of tryptase in the serum specimen.(Package insert: ImmunoCAP Tryptase. Phadia AB; 10/2019)