Update Type: New Tests
Test Updated: 02/09/2022
Test Overview
Test Methodology

Fluorescence Enzyme Immunoassay (FEIA)

Test Usage

Assessing possible mast cell activation, which may occur as a result of anaphylaxis, allergen challenge, or mast cell activation syndrome. Assessing possible systemic mastocytosis, with increased number of mast cells.

Reference Range *

<11.5 ng/mL

* Reference ranges may change over time. Please refer to the original patient report when evaluating results.

Test Limitations

Tryptase levels might not be elevated in patients with acute mast cell activation if specimen is obtained >12 hours after anaphylaxis.

Test Details
Days Set Up
Twice weekly. Tuesdays and Thursdays.
Soft Order Code
MiChart Code
Tryptase, Serum
Chemical Pathology
Special Chemistry
Specimen Requirements
Collection Instructions

Collect in an SST or red top tube. Centrifuge and transfer serum into plastic aliquot tube. Freeze aliquot (refrigeration acceptable).

Alternate Specimen
Red top serum.
Normal Volume
0.5 mL serum
Minimum Volume
0.2 mL serum
Storage Temperature
Refrigerated at 2 - 8 °C, stable 7 days.
Freeze at -20 °C for longer storage.
CPT Code
Fee Code