Sterilization, Disinfection, and Infection Control
Levels of Microbial Control
Candidates must differentiate sterilization (destroys all microorganisms including spores) from disinfection (high, intermediate, low) and sanitization. Know that sterilization methods include moist heat (autoclave), dry heat, ethylene oxide, hydrogen peroxide, and radiation, and that each has parameters (time, temperature, pressure, concentration). Understand that disinfection efficacy depends on the agent, concentration, contact time, and organic load.
Spaulding Classification
Know the Spaulding scheme: critical items require sterilization, semicritical items require high-level disinfection, and noncritical items require low-level disinfection. This is a classic testable framework.
Monitoring
Sterilization assurance uses physical, chemical, and biological indicators. Biological indicators are the most reliable; chemical indicators show exposure, not sterility. Understand autoclave load monitoring and the meaning of a positive biological indicator.
Traps
Questions often conflate disinfection with sterilization, or claim a chemical indicator proves sterility. Another trap: assuming alcohol is a sterilant - it is a disinfectant with limited sporicidal activity. Also watch for contact time being ignored in an answer choice.
Rule of Thumb
If an item will contact sterile tissue or the bloodstream, it is critical and must be sterilized; if it contacts mucous membranes, it is semicritical and needs high-level disinfection.