When allergy is suspected, one of the most common tests advised is the IgE antibody blood test. Many patients get the report but don’t understand it, or worry when a value is marked “high”. In this video, Dr. Dipak Viradia, Chest Physician & Intensivist, explains what this test measures, its types, and how results should be interpreted.

What is IgE? IgE (Immunoglobulin E) is an antibody produced by the immune system. In people with allergy, the body makes IgE against harmless substances like dust mites, pollen, mould, pet dander or certain foods. When the person is exposed again, this IgE triggers the release of histamine and other chemicals that cause allergy symptoms.

Two Types of IgE Tests

1. Total IgE. This measures the overall amount of IgE in the blood.

• A raised total IgE suggests an allergic tendency, but it does not tell you what you are allergic to.
• Total IgE can also be high in parasitic (worm) infections, eczema, and certain lung conditions.
• A normal total IgE does not rule out allergy.
• Very high levels are an important clue for ABPA (Allergic Bronchopulmonary Aspergillosis), a fungal-allergy condition of the lungs seen in some asthma patients, and are used to monitor its treatment.

2. Specific IgE. This measures IgE against individual allergens, such as house dust mite, cockroach, pollen, mould (including Aspergillus), cat, dog, or specific foods.

• It helps identify exactly what you are sensitised to.
• Results are usually reported as a number and sometimes a class (from 0 to 6), where higher values indicate stronger sensitisation.

Understanding Your Report: Important Points

• Positive does not always mean allergy. A positive specific IgE shows that your immune system is sensitised to a substance. It means allergy only if you also get symptoms on exposure. Many people test positive to something that never troubles them.
• The level doesn’t always match severity. A higher value suggests a greater chance of reaction, but it does not reliably predict how severe symptoms will be.
• Results must be read with your history. Your doctor combines the report with your symptoms, the timing and triggers, and sometimes a skin prick test or lung function test, to reach a diagnosis.

Advantages of the IgE Blood Test

• A single blood sample, no fasting needed
• Not affected by anti-allergy tablets, so medicines don’t need to be stopped (unlike the skin prick test)
• Useful for young children, people with widespread skin disease, or those at risk of reaction to skin testing

IgE test vs skin prick test. Both identify allergic sensitisation. The skin prick test gives quick results in the clinic and is very sensitive, while the blood test is useful when skin testing isn’t suitable. Your doctor will choose the right one for you.

Avoid IgG “food intolerance” tests. IgG panels sold for food allergy or intolerance are not reliable for diagnosing allergy and can lead to unnecessary food restrictions. Only IgE-based tests, interpreted by a doctor, are used for allergy diagnosis.

Dr. Dipak Viradia
Chest Physician & Intensivist | Interventional Pulmonologist & ECMO Specialist
Rudrax Chest Clinic, 301, Solaris Royce, Opp. Old RTO, Athwagate, Ring Road, Surat – 395001
Appointment: +91 75676 19985
Website: www.drdipakviradia.com