It is now possible to identify food or chemical intolerance by doing a test that analyses the mediators released after the exposure of the blood cells to the suspected foods or chemical substances. 2 similar tests are available currently and they are called Cellular Allergen-Specific Test (CAST) and the Food Allergen Cellular Test (FACT).

Both of these test are currently under clinical investigations and have been shown to be about 80% accurate in identifying the trigger chemical or food protein responsible for the symptoms. However at the moment these are the only in vitro tests available for the identification for intolerance to food proteins or chemicals.

Since food intolerance reactions are delayed for up several hours and often for one to two days, it is often very difficult to identify the offending food causing the symptoms. Some of the reasons food intolerance get worse as we get older is because of repeated consumption of the same foods day after day and also the decreased enzymatic ability to process the food proteins.

The blood test for intolerance is complex and can only be performed in specialized laboratory. When triggered in vitro by food proteins or chemicals to which a person is sensitive, sensitized blood leukocytes release a range of chemical mediators, including a group of chemicals known as leukotrienes that are responsible for a number of symptoms associated with the hypersensitivity response.

The test measures these specific mediators of the sensitivity reaction. Many types of natural foods, food colorings and food additives can be tested. The test therefore, in part, enables the underlying cause of the behavioral and emotional symptoms to be identified.

The avoidance of the offending foods through appropriate nutritional program usually brings long-term benefits. Psychological and behavioral modification therapy would then be more effective to help the sufferer "catch up" and normalize his or her behavior.

Without identifying the actual cause of these symptoms and having the various labels such as ADD, dyslexia or autism might not help us to manage the problem.