Labs from a typical lab are good for basic testing but when you need more advanced analysis, specialty labs are required. As an example, most doctors will test toxic metals like lead and mercury with only blood serum results. Blood testing only measures for acute exposure or what you are presently being exposed too. A challenge test with chelating agents are essential to determine your body burden of toxic metals that are stored in your tissues. This example repeats itself when assessing vitamins, minerals, gastrointestional health, and heart health among others.