Abstract
Answer D. Skin prick test
Skin prick tests can be carried out in allergy clinics to help identifying a particular allergen causing sensitivity reactions. An Immunoglobulin E blood test is a fairly basic test and will not identity a specific allergen. Although food challenges can be done, they are usually offered to prove a patient is no longer sensitive to that agent. Serum tryptase levels can be useful, but are usually done in the hospital setting and need to be done within minutes of an anaphylactic reaction followed by serial measurements.
InnovAiT article: Anaphylaxis. DOI: 10.1177/1755738019861988.