Cleaning, Sterilization, and Disinfection
Domain 8 - Cleaning, Sterilization, and Disinfection
This domain tests correct reprocessing decisions: matching device classification to the required level of processing and verifying that the process actually worked.
Core rules
- Spaulding classification: critical (enters sterile tissue or the vascular system - sterilize); semicritical (contacts mucous membranes or nonintact skin - high-level disinfection minimum); noncritical (touches intact skin only - low-level disinfection).
- Cleaning always comes first; organic soil and biofilm inactivate disinfectants and shield organisms from steam.
- Disinfectants must be used at the labeled dilution, temperature, and contact time; high-level disinfectants are monitored for minimum effective concentration.
- Sterilization: steam, ethylene oxide, hydrogen peroxide gas plasma, dry heat, peracetic acid. Heat- and moisture-sensitive devices need low-temperature methods.
- Monitor every load: mechanical (gauges, printout), chemical indicators (external and internal), and biological indicator - Geobacillus stearothermophilus for steam, Bacillus atrophaeus for EO. A positive BI means quarantine and recall back to the last negative BI.
- Storage: event-related shelf life is accepted - sterility holds as long as packaging is intact and dry and handling is correct.
Worked example
The steam sterilizer's weekly biological indicator turns positive. Reasoning: quarantine everything processed since the last negative BI, notify receiving units, recall and reprocess affected items, review loading and cycle parameters, and repeat BI testing with controls. Release no load until three consecutive negatives; document the investigation and any patient look-back.
Traps
Choosing low-level disinfection for an endoscope; skipping the leak test and manual cleaning before high-level disinfection; assuming alcohol wipes sterilize; releasing a load on chemical indicator results alone; storing scopes wet; forgetting that prion-contaminated instruments need special protocols or single use.