Tige

Total IgE (tIgE) is the concentration of immunoglobulin E in the blood. IgE is a class of antibody involved in allergic reactions and defense against parasites. tIgE represents the sum of all IgE molecules, regardless of their antigen specificity, and is distinct from allergen-specific IgE (sIgE), which measures IgE binding to particular allergens.

Measurement and reporting: tIgE is measured in serum or plasma by immunoassays such as nephelometry or enzyme-linked immunosorbent assay (ELISA). Results are reported in international units per milliliter (IU/mL) or kilounits per liter (kU/L). Reference ranges vary by age and laboratory; many adults have tIgE values below roughly 100–150 kU/L, but values differ widely across assays and populations.

Clinical interpretation: Elevated tIgE is associated with atopy and allergic diseases, including atopic dermatitis, allergic rhinitis, and asthma, as well as with certain parasitic infections. Very high levels can occur in hyper-IgE syndromes and other immunologic disorders. Low tIgE is common in the general population and does not exclude allergic disease. IgE levels are influenced by genetic factors, environmental exposures, smoking, obesity, and age.

Uses and limitations: tIgE is not a diagnostic test for a specific allergy and has limited sensitivity and specificity for predicting atopy. It is often measured as part of an initial evaluation, with subsequent sIgE testing or skin testing to identify relevant allergens. In some contexts, serial tIgE measurements may be used to monitor disease activity or response to therapy, though this is not routine for most allergic conditions.

Understanding tIgE requires integration with clinical history and targeted testing to interpret its significance.