Daijiworld Media Network – New Delhi
New Delhi, Oct 4: If you've ever stared at an allergy test report and felt like it was written in an alien language, you are not alone. From IgE levels and RAST/ImmunoCAP tests to mysterious terms like Class 2 sensitisation, many Indians are puzzled by what these results actually signify.
According to the Indian Council of Medical Research (ICMR), respiratory and food allergies have surged in the past decade, especially in urban areas, fueled by pollution, processed foods, and changing lifestyles. Yet, understanding the test reports remains a challenge for patients.
Understanding allergy tests
An allergy occurs when the immune system mistakenly identifies harmless substances—like dust, pollen, milk, or shellfish—as dangerous, producing an antibody called Immunoglobulin E (IgE). Allergy tests help doctors pinpoint these triggers through two common methods:
• Skin Prick Test (SPT): Small amounts of allergens are placed on the skin, and reactions like swelling or redness indicate sensitivity.
• Blood Test (IgE/RAST/ImmunoCAP): Measures the level of allergen-specific IgE antibodies in the blood, useful for children, patients on medication, or those with skin conditions.
Making sense of IgE and class numbers
Reports often list allergens with IgE values and classes:
• IgE value (kU/L): Indicates how strongly the immune system reacts. Higher numbers mean a stronger response.
• Class 0-6: Reflects levels of sensitisation, not symptom severity.
o Class 0 – No sensitisation
o Class 1-2 – Mild to moderate
o Class 3-4 – High
o Class 5-6 – Very high
A “Class 4” reading doesn’t always mean severe symptoms, and a “Class 1” may still cause noticeable reactions. Doctors interpret results along with your clinical history.
Total vs Specific IgE
• Total IgE shows overall antibody levels; high levels indicate general allergic tendencies.
• Specific IgE identifies reactions to individual allergens, helping pinpoint exact triggers.
Why results aren’t always clear-cut
• Sensitisation does not equal an allergy. Positive results may not always cause symptoms.
• Cross-reactivity can lead to reactions to similar proteins in different allergens.
• Testing panels vary; Indian labs focus on local allergens.
• IgE levels can fluctuate depending on exposure, infections, or medications.
Despite the complexity, allergy testing is invaluable. It helps doctors identify triggers, distinguish between true allergies and irritants, and guide patients in managing symptoms. As specialists emphasise, an allergy report is not a verdict—it is a snapshot of your immune system, and its numbers only make sense in context.