Test Details: Food Intolerance is a digestive system response to a particular food. Food Intolerance test helps to detect our intolerance or sensitivity to the food items we eat. It is also known as a food sensitivity test. Food sensitivity is a delayed reaction by the IgG antibody which is the most abundant antibody in our body. When we eat food and have an intolerance or sensitivity to it, IgG will give delayed reaction and studies show that this gives you a feeling of fatigue, headache, and joint pain.