Disinfectants are categorized into how many tiers in the framework described?

• A. 2
• B. 3
• C. 4
• D. 5

Answer: (B)

Three levels of disinfection provide a graded approach that matches the risk and the item being treated. The lowest level is used for noncritical surfaces that touch intact skin, so the disinfectant need only kill common bacteria and many viruses and fungi. The middle level broadens activity to inactivate mycobacteria along with a wide range of bacteria and viruses, which suits items that contact mucous membranes or nonintact skin but don’t penetrate sterile tissues. The highest level aims to destroy nearly all microbes, including many difficult pathogens, and is used for semicritical devices that contact mucous membranes or non-sterile body sites when sterilization isn’t feasible. This framework helps choose the right disinfectant based on the item’s risk of transmission and the practicality of sterilization versus disinfection.