Blood test to determine allergies: what to know

The sample is tested for allergen-specific immunoglobulin E, often called IgE. A result may show sensitisation to an item such as a food, dust mite, pollen, mould, or animal protein. Sensitisation does not always mean that exposure causes symptoms, so the history of timing, symptoms, and amount matters. A negative result also does not rule out every type of allergy or an intolerance.

Give the clinician a clear account of reactions, including what you encountered, how quickly symptoms appeared, and whether treatment was needed. Ask before changing antihistamines or other medicines; some blood tests can be done while taking them, but the clinic should decide. Do not remove several foods from your diet based only on a panel result. A clinician may recommend focused testing, a skin test, supervised exposure, or another explanation for symptoms.

Call emergency services immediately for swelling of the tongue or throat, breathing difficulty, faintness, or rapidly spreading symptoms after exposure. These can signal anaphylaxis and should not wait for test results. Arrange a routine appointment for recurrent hives, wheezing, vomiting, or nasal symptoms so the trigger and an action plan can be assessed.

Which allergens should be tested based on my history? What does a positive or negative result mean for me? Should I carry emergency medicine? Could a condition such as coeliac disease or another problem explain these symptoms?