What is the Tryptase test?

The Tryptase test measures the level of tryptase, an enzyme released by mast cells when they are activated. Mast cells play a key role in allergic and immune responses, particularly during severe reactions.

Tryptase levels rise during systemic allergic reactions such as anaphylaxis and may remain persistently elevated in certain mast cell disorders. Measuring tryptase helps assess whether symptoms are related to mast cell activation rather than other causes.

This test is commonly used in allergy, immunology, and emergency investigations.

Why do I need a Tryptase test?

Severe allergic reactions and mast cell disorders can present with sudden or unexplained symptoms. Identifying mast cell involvement is crucial for accurate diagnosis.

You may need this test if you experience:

• Severe allergic reactions
• Suspected anaphylaxis
• Sudden flushing or skin redness
• Unexplained fainting or low blood pressure
• Recurrent hives or swelling
• Gastrointestinal symptoms linked to allergies
• Suspected mast cell activation syndrome
• Investigation after a severe reaction

Testing helps clarify whether mast cells played a role in the reaction.

Benefits of the test

1. Key marker of mast cell activation
   Identifies involvement in allergic reactions.
2. Supports anaphylaxis investigation
   Helps confirm severe allergic responses.
3. Useful in mast cell disorders
   Detects persistently elevated tryptase levels.
4. Guides allergy evaluation
   Helps direct further specialist testing.
5. Objective biochemical marker
   Provides measurable evidence of mast cell activity.
6. Simple blood-based testing
   Requires only one blood sample.
7. Widely used in clinical practice
   Standard test in allergy and immunology.
8. Supports long-term monitoring
   Useful in follow-up of mast cell conditions.

Step-by-step: How we offer testing

Clinic-based testing (UK-wide)

• Choose your nearest UK clinic
• Attend your appointment
• A clinician draws a blood sample
• Sample is sent to the laboratory
• Results are issued once analysis is complete

Home or hotel visit (+£60, UK-wide)

• Book a mobile phlebotomist
• Blood sample taken at your home or hotel
• No need to attend a clinic
• Sample securely transported to the laboratory

Your results explained

Low / normal tryptase

• Tryptase within reference range
• UK standard (typical): <11.4 µg/L
• Suggests no significant mast cell activation

Moderately elevated tryptase

• Levels above reference range
• UK standard (typical): 11.4–20 µg/L
• May indicate recent allergic reaction or mast cell activation

High tryptase

• Markedly elevated levels
• UK standard: >20 µg/L
• Suggests significant mast cell activation or mast cell disorder

Timing of sampling relative to symptoms is important for interpretation.