|Description:||Total IgE levels are elevated in allergic disorders such as atopic eczema, allergic asthma, allergic bronchopulmonary aspergillosis, parasitic diseases such as invasive heleminthiasis and in a specific immunodeficiency termed Hyper IgE syndrome. Measurement of total IgE levels is not essential in the diagnosis of allergy. However, patients with higher levels of IgE tend to have specific IgE recognising more antigens and more complex histories.Specific allergen IgEs are effectively measured by the same techniques as total IgE. Unlike IgG, where even a strong immune response produces specific IgG which is only a tiny percentage of the total IgG, specific IgE responses tend to comprise a significant proportion of the total IgE. Indeed it may be possible to add up specific IgE levels to make the sum total IgE (which is usually above the “normal” range).
A minority of patients with “normal” total IgE levels will however have IgE against specific allergens and symptoms of allergy. Very low total IgE levels usually rule out allergy.
|Indication:||Investigation of allergic diseases, parasitic diseases, Hyper IgE syndrome.|
|Interpretation:||A raised IgE level is most comonly associated with atopy or atopic disposition. Patients with IgE responses to inhaled allergens usually have highest total IgE levels, particularly if there is also food allergy. Individual food allergies in the absence of allergy to inhaled allergens usually result in much lower total IgE. Levels of IgE are very high in parasitic diseases including worms. Specific autoimmune diseases resulting in raised IgE include Churg Strauss syndrome, pemphigoid and occasionally scleroderma.|
|Sample:||Serum Separator Tube (SST)|
|Reference range:||Adult range 0-75KU/L|
|Assay range notes:||Age related normal range. Levels rise in childhood to reach adult levels by 15-20 years. Though atopic children can have very high levels, well above the maximum value of the test which is 5000KU/L.|
|Turnaround time:||5 – 7 days|
|Analysing laboratory:||Immunology The James Cook University Hospital|