This test quantifies how much IgG one is producing to a specific food, with the assumption that high levels of IgG have a negative effect on the body. There is a specific type of immune reaction called Type 3 Hypersensitivity that can involve IgG or another antibody called IgM. When IgG is involved in triggering mediator release, this testing will be very helpful. Unfortunately, there are three very serious limitations of IgG testing: 1. High levels of IgG can be either beneficial (suppressing an immune response) or detrimental(causing an immune response). But one cannot tell which is beneficial IgG or which is detrimental IgG through IgG testing. So just because a patient has a high level to a particular food, this may actually be beneficial not detrimental. 2. IgG only plays a minor role in IBS, migraine, and fibromyalgia. Instead, research shows that Type 4 Hypersensitivity is the primary type of reaction involved in these conditions. Type 4 Hypersensitivity doesn’t involve IgG or any other antibodies. It only involves the release of mediators from white blood cells (cell-mediated hypersensitivity). 3. IgG testing cannot identify reactions to chemicals like food additives. It’s clearly documented that food chemicals play a very important role in provoking symptoms in many conditions. If one cannot identify these reactions, a test may be missing very important information that can impact patients' health.