Tryptase – serum

Last updated: Wednesday, 31, March, 2004

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Item Process
Specimen

5 mL blood in plain tube.

 The samples should be obtained within 6 hours of the event under investigation, with 1-2 hours being optimal.

Post-mortem blood is also suitable, if collected within 4 days of death, provided that death did not follow the event by less than 30 minutes.

Method

Immunoassay.

Reference Interval

<13 u/mL.

Application

To identify anaphylaxis as a cause of collapse, hypotension or death, eg, during anaesthesia, after insect sting, administration of drugs or biological agents (eg, desensitisation vaccines).

For follow up of mastocytosis.

Interpretation

Increased tryptase levels indicate mast cell degranulation with mediator release, thereby demonstrating an allergic basis for the reaction.

A negative result does not exclude an allergic basis especially with anaphylaxis following food ingestion.

Reference

Tang AW. Am Fam Physician 2003; 68(7): 1325-1332.