Dr Randy Tjang1, Dr Lachlan Wasson1, Dr Samantha Quoy1,2,3, Dr Emily Ong1, Dr Charmaine Lye1,2,3, Ms Teresa Lewis1,2, Ms Sally Munoch1,2, Dr Sarah Browning1,2,3
1Hunter New England Local Health District, Newcastle, Australia, 2Hunter Medical Research Institute, Infection Research Program, Newcastle, Australia, 3University of Newcastle, School of Medicine and Public Health, Newcastle, Australia
Biography:
Dr Sarah Browning is the Clinical Director of the Hunter New England Local Health District Infection Prevention Service. She is a Conjoint Senior Lecturer at the University of Newcastle. Dr Browning is currently completing a PhD at the University of Newcastle which focuses on the acquisition of MROs.
Abstract:
Introduction
This literature review examines international standards governing Automated Flexible Endoscope Reprocessor (AFER) final rinse water testing, aiming to compare regulatory controls intended to reduce nosocomial infections from contaminated AFERs.
Methods
Standards bodies were identified through International Organization for Standardization (ISO) member organisations. Body databases were systematically searched for English-language documents addressing AFER final rinse water testing. Where no national standard was available (e.g. proposal stage BSI ISO/NP 25224), widely adopted surrogate standards (e.g. HTM 01-06) were included. Standards analysed: AS 5369:2023 (Australia), EN/ISO 15883 (Europe/International), HTM 01-06 (UK), and ANSI/AAMI ST108 (USA). Publicly available supporting technical documents were reviewed.
Results
All standards set total viable count (TVC) limits at ≤10 CFU/100 mL but testing frequency ranges from weekly (HTM 01-06) to monthly (AS 5369, ST108) or unspecified (EN/ISO). Pathogen-specific testing is mandated in AS 5369 and HTM 01-06; ST108 omits this. Endotoxin limits vary: <30 EU/mL (AS 5369, annually), <10 EU/mL (ST108, monthly); EN/ISO applies a per-device limit (≤20 EU/device). Total organic carbon (TOC) is not addressed in AS 5369; others use it conditionally. Chemical purity (pH, ion thresholds, conductivity) is specified in HTM 01-06 and ST108, but left to manufacturer discretion in AS 5369 and EN/ISO.
Conclusion
Despite core alignment on some microbial limits, significant variation exists in test scope, frequency, and enforcement. AS 5369 aligns broadly with EN/ISO but is less prescriptive than HTM or ANSI/AAMI standards. These discrepancies underscore the need for harmonised, evidence-based standards to ensure consistent AFER performance and clearer guidance for endoscopy units.