Blood tests for asthma and allergies

A clinician may request total or specific IgE tests to look for immune sensitisation to particular allergens. The result can support a link between exposure and symptoms such as sneezing, itchy eyes, wheeze or cough, but sensitisation does not always cause symptoms. Asthma assessment also considers variable breathing symptoms and may use spirometry or other breathing measurements. A normal allergy blood test does not rule out asthma, and a positive result does not prove that every exposure triggers symptoms.

Write down when symptoms occur, possible triggers, pets, dust, workplace exposures, food reactions and current inhalers or antihistamines. Ask whether medicines need adjustment before sampling; do not stop prescribed treatment without advice. Bring previous test reports if available. Keep a symptom diary so the clinician can compare exposure, timing and response to treatment. Conditions such as [Coeliac Disease](/conditions/coeliac-disease/) or [Chronic Fatigue Syndrome](/conditions/chronic-fatigue-syndrome/) do not get diagnosed by an allergy panel.

Seek emergency care for severe breathlessness, inability to speak normally, blue or grey lips, collapse, or swelling of the tongue or throat. Use your prescribed reliever plan if you have one. Do not wait for blood-test results when breathing is rapidly worsening, because a laboratory result cannot assess the immediate severity of an attack.

Ask which allergens are being tested, what a positive result would change, whether breathing tests are needed, and how to recognise an asthma flare or serious allergic reaction.