Nutrient and Toxic Elements - Hair 24 Elements & metals Hair has a long history of successful use in detecting chronic exposure to toxic heavy metals in humans and animal models because hair concentrates heavy metals several hundred fold above concentrations found in blood. When any of the toxic heavy metals are elevated in hair, there is reason to investigate the origin of exposure. High levels in hair may reflect early chronic exposure before other signs and symptoms appear. Toxic heavy metals and essential trace elements are found in hair in levels many times higher than those found in any other tissue. 24 elements and metals are tested. *Profile not available in New York