There have been many changes in infection control in the 10 years since the last publication of isolation guidelines for hospitals by the Centers for Disease Control and Prevention (CDC). Hospitals since have used the 1988 CDC Update on Universal Precautions as a minimum because it is required by the Occupational Safety and Health Administration. Even before these changes, Lynch and Jackson described the concept of body substance isolation, which is intended primarily to decrease cross-transmission between patients. Many hospitals' universal precautions policies also incorporate the concept of body substance isolation to prevent the transmission of non-bloodborne as well as bloodborne pathogens. The 1988 CDC update states that the use of universal precautions does not eliminate the need for other category- or disease-specific isolation, or an institution's own system of isolation precautions.West Haven Veterans Affairs Medical Center in Connecticut and the University Health System and Audie L. Murphy Memorial Veterans Hospital in San Antonio, Texas, have adopted a universal precautions/body substance isolation (UP/BSI) policy as a standard for all patients in an attempt to lessen the confusion. All three hospitals are large, university-affiliated, tertiary care teaching institutions. Blood and all body fluids or tissue from all patients are considered potentially infectious and barrier precautions are used accordingly. Body substance isolation has been shown to decrease the transmission of some non-blood-borne pathogens.