Test Catalog

Test Id : TRYPA

Tryptase, Autopsy, Serum

Useful For
Suggests clinical disorders or settings where the test may be helpful

Evaluation of autopsy cases in which anaphylaxis in the context of allergen exposure or mast cell activation is a suspected cause of death

Method Name
A short description of the method used to perform the test

Fluorescence Enzyme Immunoassay (FEIA)

NY State Available
Indicates the status of NY State approval and if the test is orderable for NY State clients.


Reporting Name
Lists a shorter or abbreviated version of the Published Name for a test

Tryptase, Autopsy

Lists additional common names for a test, as an aid in searching

Mast Cell Tryptase

Specimen Type
Describes the specimen type validated for testing


Specimen Required
Defines the optimal specimen required to perform the test and the preferred volume to complete testing

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
Defines the amount of sample necessary to provide a clinically relevant result as determined by the testing laboratory. The minimum volume is sufficient for one attempt at testing.

0.2 mL

Reject Due To
Identifies specimen types and conditions that may cause the specimen to be rejected

Gross hemolysis OK
Gross lipemia OK
Gross icterus OK

Specimen Stability Information
Provides a description of the temperatures required to transport a specimen to the performing laboratory, alternate acceptable temperatures are also included

Specimen Type Temperature Time Special Container
Serum Frozen (preferred) 14 days
Refrigerated 7 days

Useful For
Suggests clinical disorders or settings where the test may be helpful

Evaluation of autopsy cases in which anaphylaxis in the context of allergen exposure or mast cell activation is a suspected cause of death

Clinical Information
Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

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 a half-life of approximately 2 hours. Severe anaphylactic reactions can lead to fatal airway, respiratory, and circulatory compromise. Anaphylaxis as a cause of death may be suspected in individuals with a known history of allergy, previous anaphylactic episodes, or based on autopsy evidence including mucous plugging, hyperinflated lungs, and petechial hemorrhages.(3) Measurement of tryptase in postmortem serum samples may be useful in investigating deaths in which anaphylaxis is suspected. However, interpretation of results can be difficult, as the reference value for routine diagnostic testing is not applicable to postmortem samples. A recent study identified a concentration of 53.8 mcg/L for postmortem tryptase, which resulted in a sensitivity of 89% and a specificity of 93% for the identification of anaphylaxis as the cause of death.(4) However, it is unclear how widely applicable this cutoff value is, given the complexities of postmortem specimen collection and biological processes.

Reference Values
Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

No established reference values

Provides information to assist in interpretation of the test results

Increased concentrations of total tryptase may indicate mast cell activation occurring as a result of anaphylaxis or allergen challenge, or it may indicate an increased number of mast cells as seen in patients with mastocytosis. However, no specific cutoff value has been widely validated for autopsy specimens.

Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

Tryptase may be low or undetectable in individuals with acute mast cell activation if specimens are obtained greater than 12 hours after an anaphylactic episode.


It is recommended that postmortem tryptase be measured in serum obtained from peripheral blood sources, such as the femoral vessels.


Postmortem tryptase concentrations may be affected by specimen collection technique and length of postmortem interval prior to specimen collection

Clinical Reference
Recommendations for in-depth reading of a clinical nature

1. Lyons JJ, Yi T: Mast cell tryptases in allergic inflammation and immediate hypersensitivity. Curr Opin Immunol. 2021;72:94-106. doi: 10.10.16/j.coi.2021.04.001

2. Platzgummer S, Bizzaro N, Bilo MB, et al: Recommendations for the use of tryptase in the diagnosis of anaphylaxis and clonal mast cell disorders. Eur Ann Allergy Clin Immunol. 2020 Mar;52(2):51-61. doi:10.23822/EurAnnACI.1764-1489.133

3. Garland J, Ondruschka B, Broi UD, et al: Post mortem tryptase: a review of literature on its use, sampling and interpretation in the investigation of fatal anaphylaxis. Forensic Sci Int. 2020 Sep;314:110415. doi: 10.1016/j.forsciint.2020.110415

4. Tse R, Wong CX, Kesha K, et al: Post mortem tryptase cut-off level for anaphylactic death. Foresnic Sci Int. 2018 Mar;284:5-8. doi: 10.1016/j.forsciint.2017.12.035

Method Description
Describes how the test is performed and provides a method-specific reference

Antitryptase, 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)

PDF Report
Indicates whether the report includes an additional document with charts, images or other enriched information


Day(s) Performed
Outlines the days the test is performed. This field reflects the day that the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time before the test is performed. Some tests are listed as continuously performed, which means that assays are performed multiple times during the day.

Monday through Friday

Report Available
The interval of time (receipt of sample at Mayo Clinic Laboratories to results available) taking into account standard setup days and weekends. The first day is the time that it typically takes for a result to be available. The last day is the time it might take, accounting for any necessary repeated testing.

2 to 5 days

Specimen Retention Time
Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded

14 days

Performing Laboratory Location
Indicates the location of the laboratory that performs the test


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Test Classification
Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR) product.

This test has been modified from the manufacturer's instructions. Its performance characteristics were determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information
Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Clinic Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.

CPT codes are provided by the performing laboratory.


LOINC® Information
Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the order and results codes of this test. LOINC values are provided by the performing laboratory.

Test Id Test Order Name Order LOINC Value
TRYPA Tryptase, Autopsy 21582-2
Result Id Test Result Name Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
TRYPA Tryptase, Autopsy 21582-2

Test Setup Resources

Setup Files
Test setup information contains test file definition details to support order and result interfacing between Mayo Clinic Laboratories and your Laboratory Information System.

Excel | Pdf

Sample Reports
Normal and Abnormal sample reports are provided as references for report appearance.

Normal Reports | Abnormal Reports

SI Sample Reports
International System (SI) of Unit reports are provided for a limited number of tests. These reports are intended for international account use and are only available through MayoLINK accounts that have been defined to receive them.

SI Normal Reports | SI Abnormal Reports