Abstract: This disclosed method improves the accuracy of testing blood for the levels of contaminants, such as lead, cadmium and mercury, in individuals. The method comprises cleaning the area where the skin will be penetrated to obtain the blood sample to remove the contaminant to be measured in the blood. The cleansing is accomplished with a cleanser formulated to remove the contaminant to be measured in the blood from the surface of the skin, the pores, sweat ducts, hair follicles and sebaceous gland ducts. The method reduces contamination of the blood sample by contaminants on, and/or in the portion of the skin through which the blood sample is drawn. A premoistened wipe can also be used that mobilizes heavy metals from the skin surface, the skin pores, sweat ducts, hair follicles and sebaceous gland ducts, and is formed with a wipe substrate material selected for its affinity to bind the toxic materials.