Value of Total IgE
IgE discovered in 1967, is the very least of the circulating antibodies. (G-A-M-D-E). IgE is probably a parasitic defense mechanism.
If we get a positive antigen specific IgE, then that is that. There really is no issue with false positives.
If we get all negatives on our antigen specific IgE tests, and the total IgE is low—then that really reinforces our non allergic diagnosis.
If we get negative antigen specific IgE results but a high total IgE, we might go on to look for missed allergies. Pediatric patients with allergic tendencies tend to elevate their total IgE prior to Antigen specific IgE. (A high total IgE points towards an allergic patient)
Other causes of a high IgE
Atopic Dermatitis (can be greater than 10,000), At least 1/3 of these patients have food allergies. (Common). Jobs (Hyper IgE) Syndrome—2,0000-3,0000 (Rare). CVID, SLE. Males, Smokers, Eczema, and Parasitic Infections cause high IgE.
If you get this, take a good history, treat the patient’s symptoms and repeat the lab test in a few months.