A total IgE measurement of 400 IU/ml is a serious condition and prompt medical attention is recommended for a definitive diagnosis. Immunoglobulin E, or IgE for short, is a kind of cytophilic antibody, whose content in the normal human body is small and its sensitivity is high. It is associated with allergic reactions, parasitic infections and skin allergies. The normal range for total IgE is <150 IU/ml (ELISA or rate-scattering turbidimetric assay). If the patient has an immunologic disease such as systemic lupus erythematosus, rheumatoid arthritis, etc., it may lead to an increase in serum total IgE. If the patient has a parasitic infection, the concentration of total IgE in the serum may be increased, and the patient may present with fever, abdominal pain, and diarrhea, which, in conjunction with the parasite test, will lead to a definitive diagnosis. In case of gammaglobulin deficiency, it may lead to low total IgE, which can be diagnosed by combining with its clinical manifestations. If the total IgE is abnormal, you can go to a specialized hospital for further examination, and then follow the doctor's instructions for treatment. In addition, it is also necessary to do appropriate physical exercise, which helps to strengthen the body, and can improve the body's immunity.