A standard of care designed to protect healthcare personnel and patients from infection by pathogenic micro-organisms, including viruses, that can be spread by blood or any other body fluid, excretion, or secretion (except sweat), whether or not they contain blood. Standard precautions also apply to contact with non-intact skin and mucous membranes. Other measures (e.g. expanded or transmission-based precautions) may be necessary in addition to standard precautions to prevent potential spread of certain diseases (e.g. tuberculosis, influenza, and varicella) that are transmitted through airborne, droplet, or contact transmission (e.g. sneezing, coughing, and contact with skin).
http://www.cdc.gov/mmwr/preview/mmwrhtml/rr5217a1.htm Guidelines for infection control in dental healthcare settings from the Centers for Disease Control and Prevention (US).