AAMI Standards for Sterilization and Disinfection

Executive Summary: The Association for the Advancement of Medical Instrumentation (AAMI) develops consensus standards for medical device processing that are essential for infection prevention in healthcare facilities. AAMI standards form the foundation of sterile processing department (SPD) operations and are referenced by regulators, accreditors, and best practice guidelines. This comprehensive guide covers key AAMI standards for sterilization and disinfection.

Understanding AAMI

AAMI is an ANSI-accredited standards development organization that creates voluntary consensus standards for medical devices. Key characteristics:

• Voluntary Standards: Not mandatory unless adopted by regulators
• Widely Referenced: FDA, TJC, CMS reference AAMI standards
• Consensus-Based: Developed with stakeholder input
• Regular Updates: Reviewed and revised every 5 years
• Technical Information Reports (TIRs): Guidance documents (non-normative)

Core Sterilization Standards

ANSI/AAMI ST79: Steam Sterilization

Comprehensive guide for steam sterilization and sterility assurance in healthcare facilities. Key requirements:

• Decontamination: Manual and mechanical cleaning procedures
• Inspection: Visual and functional testing of instruments
• Packaging: Container systems, wraps, pouches
• Loading: Proper sterilizer loading for steam penetration
• Cycle Selection: Gravity, prevacuum, flash/immediate use
• Monitoring: Physical, chemical, and biological indicators
• Documentation: Load records, BI results, equipment maintenance
• Storage: Event-related sterility maintenance

ANSI/AAMI ST58: Ethylene Oxide Sterilization

Requirements for EO sterilization in healthcare settings:

• Sterilizer Operation: EO gas sterilizer requirements
• Safety: Worker exposure limits, monitoring
• Aeration: Required aeration times for device types
• Cycle Parameters: Temperature, humidity, gas concentration, time
• Biological Indicators: Bacillus atrophaeus requirements
• Environmental Controls: Ventilation, emission controls

ANSI/AAMI ST41: Dry Heat Sterilization

• Applications: Anhydrous materials, powders, oils
• Temperature/Time: 160°C/120 min, 170°C/60 min, 180°C/30 min
• Biological Indicators: Bacillus atrophaeus spores

Low-Temperature Sterilization Standards

ANSI/AAMI ST58: Hydrogen Peroxide Gas Plasma

• Applications: Heat and moisture-sensitive devices
• Cycle Types: Standard, advanced, lumen cycles
• Limitations: Lumen length and diameter restrictions
• Biological Indicators: Geobacillus stearothermophilus
• Chemical Indicators: H2O2 indicators required

ANSI/AAMI ST40: Liquid Chemical Sterilization

• Peracetic Acid: Immersion sterilization of heat-sensitive devices
• Process Parameters: Temperature, concentration, time
• Validation: Process monitoring and verification
• Immediate Use: Devices must be used immediately

High-Level Disinfection Standards

ANSI/AAMI ST91: Flexible Endoscope Processing

Comprehensive requirements for endoscope reprocessing:

• Pre-Cleaning: Bedside cleaning immediately after use
• Leak Testing: Before every reprocessing cycle
• Manual Cleaning: Brushing, flushing all channels
• High-Level Disinfection: AER or manual HLD
• Rinsing: Sterile or filtered water rinse
• Drying: Forced air drying, alcohol flush
• Storage: Vertical hanging in ventilated cabinets
• Tracking: Endoscope-to-patient documentation

TIR34: Water Quality for Medical Devices

• Critical Water: Sterile water for final rinse
• Utility Water: Treated water for washing, steam generation
• Testing: Microbial, endotoxin, chemical testing requirements

Quality and Packaging Standards

ANSI/AAMI ST77: Container Systems

• Rigid sterilization container requirements
• Filter replacement, inspection, testing
• Compatibility with sterilization methods
• Validation testing requirements

ANSI/AAMI PB70: Barrier Performance

• Classification of barrier materials
• Testing requirements for surgical gowns, drapes
• Liquid barrier performance levels (1-4)

Monitoring and Indicators

Biological Indicators

Sterilization Method	BI Organism	AAMI Standard
Steam	G. stearothermophilus	ANSI/AAMI ST79
Ethylene Oxide	B. atrophaeus	ANSI/AAMI ST58
Hydrogen Peroxide	G. stearothermophilus	ANSI/AAMI ST58
Dry Heat	B. atrophaeus	ANSI/AAMI ST41

Chemical Indicators (ANSI/AAMI ST60)

• Type 1: Process indicator (external pack marking)
• Type 2: Bowie-Dick test indicator
• Type 3: Single-parameter indicator
• Type 4: Multi-parameter indicator
• Type 5: Integrating indicator
• Type 6: Emulating indicator

Implementation in Healthcare Facilities

• Policy Development: Align procedures with current AAMI standards
• Staff Training: Competency-based training per AAMI requirements
• Quality Monitoring: Implement monitoring per standards
• Documentation: Maintain records per AAMI recommendations
• Updates: Monitor for standard revisions (5-year cycle)

Related Resources

• Surgical Instrument Sterilization & Handling
• Autoclave Validation and Monitoring
• Medical Device Sterilization Methods
• Standards Hub