A serum IgE test measures total immunoglobulin E in the blood. Elevated IgE suggests allergic sensitization and atopic conditions (eczema, allergic rhinitis, asthma), parasitic infections, or certain immune disorders; very high or low values may indicate immune dysregulation. It supports but does not confirm specific allergies—clinical history and, if needed, specific IgE or skin testing are used together for diagnosis.

A high IgE level usually indicates allergic sensitization and is commonly seen with atopic conditions (eczema, allergic rhinitis, asthma), food allergies, or parasitic infections. It can increase risk of allergic reactions, including severe reactions in susceptible people. Persistently very high IgE may suggest rare immune disorders. Further evaluation guides treatment: avoidance, antihistamines, steroids, or specialist therapies like biologics.

Total IgE levels vary by age and lab, but <100 IU/mL is often considered normal; 100–500 IU/mL suggests possible atopy, and levels above about 500–1,000 IU/mL indicate a high likelihood of allergic disease. For allergen-specific IgE, a value ≥0.35 kU/L is commonly regarded as positive (class 1), with higher values indicating stronger sensitization.

A specific IgE allergy test measures the level of IgE antibodies in your blood to particular allergens (foods, pollens, pet dander, insect venom, or drugs). Performed from a blood sample, it helps identify sensitisation to specific triggers. Higher specific IgE suggests allergic sensitisation but doesn’t always predict symptoms; results must be interpreted with clinical history to confirm true allergy and guide management.

Normal total IgE varies by age. Approximate upper limits: infants (0–1 year) ~20 IU/mL; toddlers/preschool (1–5 years) ~60 IU/mL; school-age children (6–10 years) ~90 IU/mL; adolescents (11–15 years) up to ~200 IU/mL; adults generally under ~100–150 IU/mL. Values vary by lab; if results are high or symptoms occur, discuss with your doctor.

Seven common allergy symptoms are: 1) Sneezing; 2) Runny or blocked nose (nasal congestion); 3) Itchy, red, watery eyes; 4) Coughing; 5) Wheeze or shortness of breath; 6) Skin reactions such as hives, eczema or itching; 7) Swelling of face, lips, tongue or throat (angioedema). Seek urgent medical care for severe breathing problems or rapid swelling.