York labs is the market leader in intolerance testing. Intolerance tests are designed to pick up IgG antibodies to certain food types so you can distinguish what you are intolerant to and then exclude this item from your diet to improve your symptoms. Symptoms of intolerance include bloating, gas, wind, vomiting, allergies, skin conditions, inability to lose weight among others. Tests are performed by a finger prick blood test and then the sample is sent to the lab for analysis.