Vaporized Hydrogen Peroxide Gas Plasma Technology Explained

The combination of hydrogen peroxide and low-temperature gas plasma safely and efficiently sterilizes validated medical devices and materials, in a compliant manner. This approach is considered advantageous over alternative reprocessing modalities.

STERRAD™ Sterilization Systems utilise a combination of hydrogen peroxide (H2O2) and low-temperature gas plasma to sterilize validated medical devices and materials rapidly and safely, without creating toxic residue. By reducing hydrogen peroxide vapour emissions as detailed below, this approach offers increased safety in comparison to alternative reprocessing modalities, including ethylene oxide (EtO) and other hydrogen peroxide systems.

Exclusive Technology Unique to STERRAD™ Systems

With over 20,000 installations of STERRAD™ Systems globally, this technology is trusted to sterilize instruments by healthcare institutions around the world. Each feature of STERRAD™ Systems intentionally and directly addresses challenges that can occur in real-world reprocessing.

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Enhanced Safety

Hydrogen Peroxide Monitoring

Hydrogen peroxide monitoring in the STERRAD NX™ Sterilizer and STERRAD™ 100NX Sterilizer ensures a maintained concentration of hydrogen peroxide throughout the exposure period, to guarantee effective microbicidal activity. The STERRAD NX™ Sterilizer and STERRAD™ 100NX Sterilizer both feature control systems with fully integrated hydrogen peroxide monitors, which directly measure the chamber sterilant concentration, as standard. The hydrogen peroxide monitor provides data to the process controller, which also considers the acceptable cycle limits, as determined by statistical analysis of microbiological efficacy testing, to ascertain the acceptability of each cycle and ensure a minimum sterility assurance level (SAL) of 10-6.

STERRAD™ System’s in-built, continuous hydrogen peroxide monitor is comprised of an ultraviolet (UV) light source and detector, which records fluctuating interactions between hydrogen peroxide vapour and UV light intensity. When hydrogen peroxide declines to a concentration below a defined threshold for sterilization the UV light intensity changes, signalling for the sterilization cycle to be halted.

Gas Plasma

STERRAD™ Systems, also referred to as Vaporised Hydrogen Peroxide Gas Plasma Sterilization or Low Temperature Sterilization, directly remove residual hydrogen peroxidefrom the chamber and instruments using an exclusive gas plasma technology. As hydrogen peroxide diffuses through the chamber and surrounds the loaded instrument, the low-temperature gas plasma is ignited via the application of an electric field. As a result of the plasma, the hydrogen peroxide vapour splits into free radicals. When the electric field through the plasma is terminated, the free radicals lose their high-energy state and recombine as oxygen and water vapour.


Gas Plasma Process

STERRAD™ Systems emit significantly less hydrogen peroxide than STERIS® VPRO-Sterilizers, minimising the hydrogen peroxide exposure that healthcare workers receive when opening the sterilizer door VPRO-Sterilizers.

In a comparative study of continuous hydrogen peroxide emission monitoring2, V-PRO® Sterilizer emissions were 67 times higher than those of STERRAD™ Systems upon opening the sterilizer door after a cycle. This highlights that STERRAD™ Systems, which use a gas plasma phase to dissociate hydrogen peroxide during the sterilization cycle, are more effective in reducing hydrogen peroxide than the STERIS® V-PRO® maX, which only passes H2O2 through a catalytic converter.

Increased Efficiency

STERRAD™ System with ALLClear™ Technology

The STERRAD™ System with ALLClear™ Technology, found in the STERRAD NX™ Sterilizer and STERRAD™ 100NX System Sterilizer, is an automatic pre-cycle system diagnosis and load conditioning technology that reduces the number of cancelled cycles. This technology can detect load issues, for example, excessive moisture, with increased speed3 and load conditioning, intelligence,4 in comparison to the STERIS® V-PRO® max sterilizer.

In accordance with a market survey,5 100% of customers agreed that STERRAD™ Systems with ALLClear™ Technology are easy to use and 80% of customers agreed that the systems reduce operator error in comparison to the legacy STERRAD™ 100NX and STERRAD NX™ Systems.


ASP ACCESS™ Technology

ASP ACCESS™ Technology is an intelligent information-sharing technology which links ASP devices to hospital networks, including instrument tracking systems (ITS). With this feature, ASP technologies can work together to help decrease human errors. Compliance with Instructions for Use (IFU) and hospital policies is made easier by on-screen, step-by-step instructions and automatic checkpoints.


The STERRAD VELOCITY™ System efficiently guides users through compliant Biological Indicator (BI) processing and automatically generates audit-ready records.

History of Vaporized Hydrogen Peroxide Gas Plasma Technology

Technological advances have transformed many aspects of medicine, for example, robotic-assisted surgical procedures, which have led to the introduction of increasingly complex surgical instruments. This has in turn posed challenges for sterilization via traditional steam autoclaves, paving the way for development of other sterilization modalities able to process delicate instruments, such as flexible endoscopes.

Whilst EtO was introduced as an alternative to steam sterilization for heat and moisture-sensitive instruments, it is associated with several disadvantages, including long sterilization cycles, high costs and potential hazards to patients and staff.1

ASP timeline

Innovation of Low Temperature Sterilization

Scientists in a Texas-based company pioneered the idea of using hydrogen peroxide for device sterilization. In 1987, this company officially formed as Advanced Sterilization Products (ASP).

ASP’s first vaporized hydrogen peroxide gas plasma sterilizer, the STERRAD™ 100 System, received U.S. Food and Drug Administration clearance in 1993. This novel technology sterilized medical devices by diffusing hydrogen peroxide vapor into the chamber before electromagnetically energising the hydrogen peroxide molecules into a low-temperature plasma state. The combined use of hydrogen peroxide vapor and plasma safely and rapidly sterilized medical instruments and materials, without producing toxic residues.

ASP continued to innovate over the years, introducing other sterilization systems such as the STERRAD NX™ System in 2005 and STERRAD™ 100NX System in 2007. Both of these systems were released with a Standard cycle for general medical instruments and a Flex cycle for single-channel flexible endoscopes. The STERRAD™ 100NX system subsequently received cycle upgrades, including an EXPRESS Cycle compatible with the Intuitive Surgical™ da Vinci™ Surgical Endoscope in 2011, and a DUO Cycle validated for flexible scopes and cameras in 2012. ASP then introduced the ALLClear™ Technology software upgrade for the STERRAD NX™ System in 2016 and the STERRAD™ 100NX System in 2017, reducing the number of cancelled cycles, increasing connectivity to the ASP ACCESS™ Data Station and hospitals’ ITS, and providing on-screen guides to increase compliance.


  1. Centers for Disease Control and Prevention (CDC). Guideline for Disinfection and Sterilization in Healthcare Facilities (2008). Ethylene Oxide “Gas” Sterilization. Accessed September 5, 2020.

  2. The research was designed and executed by Actionable Research, an independent third-party research firm in conjunction with ChemDAQ® Inc., a manufacturer of environmental safety monitoring systems. The research sponsor was Advanced Sterilization Products. All data were collected by the ChemDAQ® staff.

  3. For non-lumen and flex cycles.

  4. In STERRAD™ Systems with ALLClear™ Technology, cancellations occur before the sterilization cycle begins if the load is not optimal for sterilization.

  5. Based on market survey conducted by Advanced Sterilization Products.

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ADVANCED STERILIZATION PRODUCTS (ASP) have engaged in a commercial agreement with a market research firm to conduct a market research study. ASP respects the healthcare industry codes alongside country-wide and local laws pertaining to restrictions for healthcare professionals, including, but not limited to, the full disclosure and transfer of value in relation to market research studies, where applicable.



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