The total IgE test may be used to screen for and detect allergic diseases. It may be ordered by itself, before, or along withallergen-specific IgE tests ? depending upon whether or not a person or doctor has identified potential substances to which the person may be allergic. IgE can be increased with parasitic infections, so a total IgE test is sometimes used as a screening test if a parasitic infection is suspected. Symptoms may include those that suggest skin, respiratory, and/or digestive involvement, such as: Periodic or persistent itching Hives Itchy eyes Eczema Nausea, vomiting, persistent diarrhea Sneezing, coughing, congestion Difficulty breathing Asthma symptoms: wheezing, breathlessness, coughing, tightness in the chest Sometimes an IgE may be ordered as a screening test when a person has persistent diarrhea that may be due to aparasitic infection. In addition, a CBC with white blood cell differential may be ordered to determine if the number ofeosinophils is increased. An increased total IgE level indicates that it is likely that a person has one or moreallergies. Allergen-specific IgE levels will increase after an exposure and then decline over time, thus affecting the total IgE level. If a person is allergic to a seasonal substance, such as pollen, then both the specific IgE and total IgE would be expected to increase during the time of year when the allergen is present. If someone has one or more food allergies, then the total IgE level would mirror exposures to these foods. If someone is allergic to something that they are constantly around, such as mold in a house or cat dander, then the total IgE level may be persistently increased.An elevated level of total IgE indicates an allergic process is likely present, but it will not indicate what a person is A normal IgE level makes it less likely that a person has allergies but does not rule them out due to the length of time between exposures. In between exposures, a person's IgE level may drop. Sometimes an individual has a condition that affects their immune system and will not produce normal amounts of immunoglobulins. In this case, a person could have an allergy that is not reflected by the total IgE test result.