tryptase measurement if anaphylaxis

Last reviewed 01/2018

After a suspected anaphylactic reaction in adults or young people aged 16 years or older, take timed blood samples for mast cell tryptase testing as follows:

• a sample as soon as possible after emergency treatment has started
• a second sample ideally within 1-2 hours (but no later than 4 hours) from the onset of symptoms

After a suspected anaphylactic reaction in children younger than 16 years, consider taking blood samples for mast cell tryptase testing as follows if the cause is thought to be venom-related, drug-related or idiopathic:

• a sample as soon as possible after emergency treatment has started
• a second sample ideally within 1-2 hours (but no later than 4 hours) from the onset of symptoms.

Reference:

• NICE (December 2011). Anaphylaxis: assessment to confirm an anaphylactic episode and the decision to refer after emergency treatment for a suspected anaphylactic episode