Elevated serum IgE (>300 IU/mL) is a hallmark in allergic conditions such as asthma, atopic dermatitis, and allergic bronchopulmonary aspergillosis (ABPA). Hyperimmunoglobulinemia E syndromes (HIES), caused by STAT3 mutations, present with recurrent infections, eczema, and IgE levels exceeding 2,000 IU/mL. IgE multiple myeloma, a rare plasma cell malignancy, produces monoclonal IgE with normal structure but lambda light chain predominance, often complicating renal function. Parasitic infections and viral diseases like HIV also drive polyclonal IgE elevation. Clinically, total IgE quantification aids in diagnosing ABPA and monitoring omalizumab therapy, an anti-IgE monoclonal antibody that reduces free IgE levels by forming inert complexes. Despite its short serum half-life (2–3 days), cell-bound IgE persists for weeks on immune cells, necessitating combined plasma and cell-bound IgE measurements for accurate allergy diagnosis. Myeloma-derived IgE remains invaluable for structural studies due to its intact glycosylation and receptor-binding properties. Emerging therapies targeting IgE-FcεRI interactions and glycosylation pathways aim to modulate allergic responses while preserving protective functions.

Common uses include IVD Assay standards, calibrators and controls, therapeutics research, immune system research.