Hypersensitivity to food or to food ingredients triggers immune system response in the body and usually activates production of immunoglobulin IgG, or immunoglobulin G “subpopulations”, namely IGg1 I IGg4. The measured indicator is actually IgG4 level in the blood, which implies the “multiplication” of immune response (usually “chronic” reactions) caused by certain food. This test demonstrates hypersensitivity to food; therefore the real test name should be “the food sensitivity test”, regardless of the generally accepted, but still incorrect term, “intolerance test”.
Food (alimentary) intolerance can have similar symptomatology as food allergy, although without the life threatening clinical picture. Visible symptoms manifest within an interval between few minutes and few hours after the ingestion of certain foods (usually in an interval of 1-2 hours). It is important to note that symptoms do not appear because of immune inadequacy. They appear due to lack of a specific enzymes or chemical substances included in the food digestion process. One of the most common intolerance types is lactose intolerance. Deficiency (lack) of lactase enzyme in the small intestine does not allow milk sugar degradation (lactose).