16th February 2025

A 19-year-old lady attends the general practitioner with recurrent episodes of poorly localised abdominal pain associated with nausea, lasting up to three days and occurring twice a month for the last year.

A 19-year-old lady attends the general practitioner with recurrent episodes of poorly localised abdominal pain associated with nausea, lasting up to three days and occurring twice a month for the last year. She has also had two episodes of facial swelling affecting her face and tongue, which made breathing difficult. In between episodes, she is well. Her father suffers from similar episodes of facial swelling. 

There is no identifiable trigger and no improvement with antihistamines or corticosteroids. She has no past medical history and takes no regular medications.

Routine bloods and urinalysis including hCG (human chorionic gonadotropin) are normal.

Which next test will be most useful in establishing the likely diagnosis?

Select the SINGLE most appropriate option from the list below. Select ONE option only.