Validation of performance qualification of ultrasound probe high-level disinfection devices in clinical settings.

Background: In accordance with AS5369:2023, disinfection processes need to undergo routine performance qualification (PQ) as part of in-field validation. Automated high-level disinfection (HLD) devices therefore need to undergo PQ. Responding to reports that some ultraviolet-C (UV-C) devices used for reprocessing of ultrasound transducers were failing to achieve sporicidal efficacy during routine PQ, we evaluated the sporicidal efficacy of these devices.

Methods: Sporicidal efficacy was assessed using commercially available stainless steel biological indicators (BIs) inoculated with 10⁶Geobacillus stearothermophilus spores (ATCC® 7953). BIs were clamped in top and bottom positions inside the chambers of the devices [UV-C light-emitting diode (LED), UV-C lamp and hydrogen peroxide (H₂O₂) mist]. All three devices were in clinical use. BI test conditions included packaged, unwrapped and non-flamed as well as unwrapped and flame sterilised on the clamped coupon end. Results were evaluated on a pass (no growth) or fail (growth) basis.

Results: The UV-C LED device failed to inactivate spores in all tested positions and conditions (n = 18). The UV-C lamp device passed 2/6 of the unwrapped and flamed tests but failed all other tests (n = 12). The H₂O₂ mist device passed all tests, inactivating spores for all conditions and chamber positions (n = 18).

Conclusion: The H₂O₂ mist device was the only device in this study that passed all tests, demonstrating sporicidal efficacy. Both UV-C devices failed to demonstrate sporicidal efficacy in this PQ study suggesting that clinicians need to monitor UV-C devices more frequently to ensure continued efficacy and patient safety.