Fluorescence Enzyme Immunoassay (FEIA)
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.
Tryptase levels might not be elevated in patients with acute mast cell activation if specimen is obtained >12 hours after anaphylaxis.
Collect in an SST or red top tube. Centrifuge and transfer serum into plastic aliquot tube. Freeze aliquot (refrigeration acceptable).
Freeze at -20 °C for longer storage.