Tryptase

Specimen:

5 mL blood in plain tube.

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