Different types of indicators monitor different aspects of the sterilization process (see Figure 3.8). For example, autoclave tape, ethylene oxide (ETO) tape, and steam strips (see Chapter 3) indicate whether the appropriate conditions for sterilization have occurred (e.g., sufficient temperature or pressure). These are included in every autoclave and ETO load. They are helpful for determining if something has been autoclaved, but they do not tell us whether the object is actually

sterile. Steraffirm® indicators (see Figure 3.8) are used to verify sterilization of water. Like autoclave tape, they change color (from red to green) when the correct temperature has been reached rather than indicating whether the load is sterile. Steraffirm® tubes measure two critical parameters: time and temperature (see “Water Sterilization” on page 122).