IgESerumtests

IgE serum tests measure the amount of immunoglobulin E (IgE) antibodies in a person’s blood. They are used to assess allergic sensitization and, together with clinical history, to support the diagnosis of allergic diseases such as allergic rhinitis, asthma, and atopic dermatitis. Tests are typically divided into total IgE and specific IgE. Total IgE quantifies the overall level of IgE in the serum and can be elevated in atopy, parasitic infections, and some other conditions, but it is not specific for a particular allergen. Specific IgE tests detect IgE antibodies directed against individual allergens, including pollens, foods, house dust mites, animal dander, and insect venom.

Methods and results: Specific IgE testing is performed with immunoassay techniques, including enzyme-linked immunosorbent assays (ELISA) and fluorescence-based assays, on commercial platforms such as ImmunoCAP or FEIA. Results are reported as concentrations (for example kilounits per liter, kU/L) or as a qualitative/graded class (0 to 6) depending on the test. Values are interpreted in the context of age, geography, and exposure history. A positive specific IgE indicates sensitization to the tested allergen but does not by itself prove clinical allergy; a negative result reduces the likelihood but does not entirely exclude it.

Indications and limitations: IgE serum testing is useful when the history suggests allergic disease and when skin prick testing is impractical or equivocal. It can help guide allergen avoidance and the selection of candidates for immunotherapy. Limitations include cross-reactivity between allergens, variability in reference ranges, and poor correlation between IgE level and symptom severity. False positives and negatives can occur, and results should be integrated with clinical findings.

Sample and safety: testing requires a blood sample drawn by venipuncture. The procedure is routine and generally safe.