Definition
- IgE mediates allergic and hypersensitivity reactions. There is a significant overlap in total IgE between allergic and nonallergic individuals. Measurement of total IgE is not very useful as a standalone screen for allergy disease.
- Normal values: see Table 16.42.
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TABLE 16 " “42Normal Values for IgE by AgeView LargeTABLE 16 " “42Normal Values for IgE by Age Age (y) Value (kU/L) 0 " “2 <53 2 <93 3 <120 4 <160 5 <192 6 <224 7 <248 8 <260 9 <304 10 <328 18 <127
Use
- For allergy testing; IgE antibodies and skin tests are essentially interchangeable.
- Indicates various parasitic diseases.
- Diagnosis of E-myeloma.
- Diagnosis of bronchopulmonary aspergillosis; a normal serum IgE level excludes the diagnosis.
Interpretation
Increased In
- Atopic diseases
- Exogenous asthma in approximately 60% of patients
- Hay fever in approximately 30% of patients
- Atopic eczema
- Influenced by type of allergen, duration of stimulation, presence of symptoms, and hyposensitization treatment
- Parasitic diseases (e.g., ascariasis, visceral larva migrans, hookworm disease, schistosomiasis, Echinococcus infestation)
- Monoclonal IgE myeloma
Decreased In
- Hereditary deficiencies
- Acquired immunodeficiency
- Ataxia " “telangiectasia
- Non-IgE myeloma
Normal In
Limitations
- A normal level of IgE in serum does not eliminate the possibility of allergic disease.