Some heavy metals, in trace amounts, are beneficial to the body; these include iron, zinc, copper and manganese. Other heavy metals can be poisonous or toxic to the human body; these include arsenic, lead, mercury, cadmium, iron, and others. These metals manifest themselves within the soft tissues of the body and may cause gastrointestinal, neurological, and other serious illness if left untreated. More people are undergoing heavy metal testing, via Live Blood Cell Analysis or Hair Mineral Analysis, to seek answers to some of their acute or long-term health issues. Still others ask for testing to get ahead of any potential health problems.