What is the purpose of administering a mast cell tryptase sample?

Administering a mast cell tryptase sample serves specifically to confirm the diagnosis of anaphylaxis. Tryptase is an enzyme released by mast cells during an anaphylactic reaction. Elevated levels of this enzyme in the blood can indicate acute mast cell activation, which is a hallmark of anaphylaxis. Measuring tryptase levels shortly after the onset of symptoms can support the diagnosis, particularly in situations where clinical features may be ambiguous or the history of a known allergy is unclear.

This is especially important because the identification of anaphylaxis is critical for the timely administration of life-saving treatments, such as epinephrine. The timing of blood draw is crucial; levels are typically obtained within two to three hours after an anaphylactic event for optimal accuracy in interpretation.

In contrast, while determining a patient's response to medication could be useful in various clinical situations, it is not the primary purpose of measuring mast cell tryptase. Similarly, measuring blood pressure changes is crucial in assessing the physiological response during anaphylaxis but does not specifically involve mast cell tryptase levels. Identifying other allergies is also a different aspect of allergy assessment and does not pertain to the immediate evaluation of anaphylaxis.