Serum or plasma mass concentration of mast cell tryptase

What Is Mast Cell Tryptase Used For?

Mast cell tryptase is primarily used to diagnose or monitor conditions where mast cells release excessive tryptase, such as mastocytosis (a rare disorder where too many mast cells build up in the body) or severe allergic reactions. It can also help assess the effectiveness of treatments for these conditions.

How Is the Test Performed?

A blood sample is drawn from a vein, usually in your arm. The sample is then sent to a lab where it is processed to measure tryptase levels. The test is typically done after fasting, though this may vary by facility.

What Does a High or Low Tryptase Level Mean?

Elevated tryptase levels often indicate recent or ongoing mast cell activation, which can be linked to allergic reactions, anaphylaxis, or mastocytosis. However, normal levels do not rule out these conditions, so further evaluation may be needed. Low levels may suggest fewer active mast cells, but this is less commonly evaluated in routine testing.

When Might You Need This Test?

Your healthcare provider may order this test if you have symptoms like severe allergic reactions, unexplained skin rashes, gastrointestinal issues, or other signs of mast cell activation. It may also be used to monitor treatment progress in patients with known mast cell disorders.