Medical instruments that come in contact with patients' blood and body fluids during invasive procedures should be sterilized after use. Some instruments, however, are too delicate to tolerate auto-clave temperatures, even the lower temperature required by ethylene oxide sterilization. Chemical sterilants are an acceptable alternative but present a different problem because they require prolonged soaking time from six and three-quarters to ten hours. This long exposure to liquids may adversely affect the components of some instruments. Therefore, the manufacturer should always be consulted when prolonged soaking is contemplated.

Another disadvantage to prolonged sterilization cycles is the increased number of instruments that may be required to compensate for the lag in availability. As an acceptable alternative, the Centers for Disease Control (CDC) and others have divided instruments into three categories: instruments that enter normally sterile tissue and the vascular system (these must be sterilized); instruments that contact nonintact skin and mucous membranes (these should receive high-level disinfection); and items that contact only intact skin such as blood pressure cuffs (these require a lower level of disinfection and will not be discussed here). Importantly, it should be noted that the Environmental Protection Agency (EPA), which registers chemical disinfectants/sterilants, does not recognize these categorizations. They register solutions for sterilization or disinfection.