Tryptase is one of the hundreds of mediators released by the mast cells when they have been triggered to degranulate for any reason.
Tryptase is a protease, or an enzyme that helps break down proteins, that is often elevated during an allergic reaction. According to Dr. Glenn Reeves of the Hunter Area Pathology Service, tryptase is seen only in mast cells. During an anaphylactic reaction, your levels of serum tryptase elevate within an hour and stay this way for four to six hours. Certain foods and food additives can cause an allergic reaction and result in raised blood levels of tryptase
Blood tryptase levels are thought to reflect the quantity of mast cells that may be in the body and a level of greater than 20ng/ml is currently believed to be the level to suggest that the bone marrow has been infiltrated by mast cells. As tryptase levels can rise after anaphylaxis, it is therefore important that the tryptase level is measured when the patient is at his/her baseline level of health and not during or soon after an anaphylactic reaction. It is important to remember a tryptase level of greater than 20ng/ml alone does not lead to a diagnosis of systemic mastocytosis.