This test detects the levels of IgG antibodies in the body that are produced because of the consumption of a certain food. The levels of IgG are measured for various foods and an abnormal range of IgG needs immediate medical attention and changes in the diet. It is one of the most effective ways to test intolerance for a specific category of foods. If the levels of IgG are higher than normal, it can be managed by eliminating those foods that you are intolerant to. By doing so, the recovery can become easier and more effective.