IgE and IgG tests are usually available for people who would like to test if they have certain allergies. Food allergies can be very stressful especially if you do not know what is potentially causing your allergies. Taking the test will allow you to know what you need to look for. IgE means that there is an immediate response to a substance that the body does not recognize so it is being targeted by the body.
For IgG, something that is not being tolerated too well by the body will not manifest immediately. This might mean that the symptoms are going to be milder but at the same time, the effect of this type of allergy will also last longer. Undergoing the test will help you know what you can take and what you should avoid.