Which class of chemical indicator is placed externally to show that the item has been exposed to the sterilization process?

• A. Class II
• B. Class I
• C. Class III
• D. Class IV

Answer: (B)

External indicators signal that the sterilization cycle reached the item by being placed on the outside of a pack. They’re designed for a quick visual check that the item was exposed to the sterilant, not to prove complete sterility or verify every parameter inside the load. This type of indicator is Class I, often seen as autoclave tape that color-changes with exposure to the sterilization conditions. Other indicators serve different roles: internal process indicators (Class II) verify that the sterilization process occurred inside the package, single-parameter indicators (Class III) monitor one critical factor at a location, and multi-parameter indicators (Class IV) assess several variables in combination. So, for showing external exposure of the item to the sterilization process, the best fit is Class I.