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Mast Cell Tryptase

General information

Specimen transport: At room temperature

Repeat frequency: For suspected anaphylaxis samples should be taken as soon as possible after emergency treatment, 1-2 hours post treatment (but no later than 4 hours post) and a baseline sample at >24 hrs post treatment.

For mastocytosis repeat after 1 year or following significant clinical change.

Special precautions: For suspected anaphylaxis the first sample should be obtained as soon as possible after the patient's condition has been stabilised.

Laboratory information

Normal reference range: 0-12.9 ug/l

Volume and sample type: 7ml clotted blood

Method: FEIA (Fluoroenzyme Immunoassay)

Turnaround time (calendar days from sample receipt to authorised result): Median - 1

Clinical information

Indications for the test: Suspected acute allergic reactions, anaphylaxis, suspected Mastocytosis

Factors affecting the test: Tryptase levels decline following an adverse reaction. The decline in tryptase levels can be confirmed providing that two blood samples are obtained (each indicating the time it was taken). 40% of the Manchester population is alpha tryptase deficient. This may affect the normal range but future research is needed.


ICE reference: Mast Cell Tryptase


(Last updated August 22nd 2018)