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

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.

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.

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).

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.