Vaporized Hydrogen Peroxide Gas Plasma Technology

STERRAD® Sterilization Systems utilize a combination of hydrogen peroxide (HO2) and low-temperature gas plasma to rapidly and safely sterilize validated medical devices and materials, without leaving toxic residue. This approach offers safety advantages over alternative reprocessing modalities such as ethylene oxide (EtO) and other HO2 systems by reducing HO2 vapor emissions, as described below.

Exclusive Technology Unique to STERRAD® Systems

With over 20,000 STERRAD® Systems installed globally, it is trusted by healthcare institutions around the world to terminally sterilize instruments. Features of STERRAD® Systems are not superfluous; rather each are deliberate and intentional to directly address challenges that may occur in real-world reprocessing.

Enhanced Safety

Hydrogen Peroxide Monitoring

Hydrogen peroxide monitoring in the STERRAD NX® Sterilizer and STERRAD® 100NX Sterilizer ensures concentration levels of hydrogen peroxide are maintained during the exposure period for effective microbicidal activity. The STERRAD NX® Sterilizer and STERRAD® 100NX Sterilizer feature a control system with a fully integrated hydrogen peroxide monitor as a standard equipment for direct measurement of the chamber sterilant concentration. The hydrogen peroxide monitor provides data to the process controller which uses this data and information on acceptable cycle limits determined by statistical analysis of microbiological efficacy testing to make decisions regarding the acceptability of each cycle and ensure a minimum sterility assurance level (SAL) of 10-6.

STERRAD® System’s built-in continuous hydrogen peroxide monitor consists of a UV light source and detector that senses fluctuations in the interaction between the hydrogen peroxide vapor and UV light intensity. When the concentration of hydrogen peroxide drops below a defined threshold for sterilization, the UV light intensity changes, signaling the system to abort the sterilization cycle.

Gas Plasma

STERRAD® Systems, also referred to as Vaporized Hydrogen Peroxide Gas Plasma Sterilization, utilize an exclusive gas plasma technology to directly remove hydrogen peroxide residual from the chamber and instruments. Once hydrogen peroxide diffuses through the chamber and surrounds the instrument in the load, the low-temperature gas plasma is ignited by applying an electric field. Plasma causes the hydrogen peroxide vapor to break apart into free radicals. When plasma energy is terminated, the free radicals lose their high energy state and recombine as oxygen and water vapor.


STERRAD® Systems minimize healthcare worker exposure to hydrogen peroxide when opening the sterilizer door after a completed cycle and emits significantly less hydrogen peroxide than STERIS® VPRO-Sterilizers.

In a side-by-side comparative study2, continuous hydrogen peroxide emissions monitoring of STERRAD® Systems and STERIS® V-PRO® Sterilizers resulted with V-PRO® Sterilizers emissions registering 67 times higher than those of STERRAD® Systems when opening the sterilizer door after a cycle. The results of the study demonstrate that STERRAD® Systems which uses a gas plasma phase to dissociate hydrogen peroxide during the sterilization cycle, is more effective in limiting hydrogen peroxides than the STERIS® V-PRO® maX, which only passes hydrogen peroxide through a catalytic converter.

Increased Efficiency

STERRAD® System with ALLClear® Technology

STERRAD® System with ALLClear® Technology found in the STERRAD NX® System and STERRAD® 100NX System sterilizers is an automatic pre-cycle system diagnosis and load condition technology that minimizes cancelled cycles. STERRAD® System with ALLClear® Technology can detect load issues such as excessive moisture faster3 and is more intelligent with load conditioning4 than the STERIS® V-PRO® maX sterilizer.

According to a Market Survey5, 100% of customers agree that the STERRAD® System with ALLClear® Technology are easy to use and 80% of customers agree that the systems reduce operator error as compared to the legacy STERRAD® 100NX System and STERRAD NX® Systems.


ASP ACCESS® Technology

ASP ACCESS® Technology is a smart information-sharing technology that links ASP devices with hospital networks including instrument tracking systems (ITS). ASP technologies now can work together to help reduce human errors. On-screen, step-by-step instructions with automatic checkpoints help ensure compliance with Instructions for Use (IFU) and hospital policies.


STERRAD VELOCITY® System quickly guides users through compliant BI processing and automatically generates audit-ready records.

History of Vaporized Hydrogen Peroxide Gas Plasma Technology

Advances in technology transformed many aspects of medicine such as robotic-assisted procedures in the modern world that lead to more complex surgical instruments. This posed challenges for sterilization using the traditional steam autoclave, and it paved the way for the development of other sterilization modality to process delicate instrumentation such as flexible endoscopes.

While Ethylene Oxide (EtO) was introduced as an alternative to steam sterilization for the sterilization of heat and moisture-sensitive instruments, there are many disadvantages associated with the use of EtO such as long sterilization cycles, cost and potential hazards to patient and staff.1


Innovation of Low Temperature Sterilization

A group of scientists from a company in Texas pioneered the novel 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 FDA clearance in 1993. This first-of-its-kind technology sterilizes medical devices by diffusing hydrogen peroxide vapor into the chamber and then electromagnetically exciting the hydrogen peroxide molecules into a low-temperature plasma state. The combined use of hydrogen peroxide vapor and plasma safely and rapidly sterilizes medical instruments and materials without leaving toxic residue.

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 released with a Standard cycle for general medical instruments and a Flex cycle for single-channel flexible endoscopes.  The STERRAD® 100NX system then 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, which allowed for less canceled cycles, connectivity to the ASP ACCESS® Data Station and hospital’s ITS, plus on-screen guides to increase compliance. 

Meet the Expert

John Chien

John Chien

Principal Electrical Engineer, ASP


  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. This study was funded in full or in part by an educational grant from ADVANCED STERILIZATION PRODUCTS (ASP). Product attributes sourced from the device use information for each product and not based on head-to-head studies. Not intended to convey comparative safety or effectiveness. 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.

The third-party trademarks used herein are the properties of their respective owners.

ADVANCED STERILIZATION PRODUCTS (ASP) has engaged in a commercial agreement with a market research firm to conduct a market research study. ASP respects health care industry codes and country and local laws regarding restrictions for health care professionals, included but not limited to fully disclose any transfer of value in regard to market research studies when applicable.