In yet another revision to its clearance letter for the Steris System 1E liquid chemical sterilant processing system, the Food and Drug Administration has included more specific language about the treatment of rinse water used in the system and how facilities should determine where the device fits into their instrument processing protocols.

The SS1E, designed to be a successor to the phased-out Steris System 1, was first cleared in April 2010, but language in the original FDA clearance letter has left many in the healthcare community perplexed. The letter originally stated that devices processed in the SS1E, which uses a peracetic acid germicide called S40, are rinsed with potable water that, despite going through a 3-step treatment process that involves filtration and exposure to ultraviolet rays, is not sterile.

Now, the FDA has revised this language to better explain the SS1E's rinse water treatment: "The treatment method eliminates bacteria/fungi/protozoa from the water. Studies with the test virus MS2 (EPA recommended surrogate for waterborne viruses) showed a 6 log reduction."

The letter no longer states that devices processed in the SS1E "cannot be assured to be sterile," but it does state that, as with all liquid chemical sterilant processing systems, devices should be "used immediately or stored in a manner similar to that of high level disinfected endoscopes" after emerging from the SS1E.

So when should the SS1E be used? Only to process heat-sensitive semi-critical and critical devices that are validated for use in the system, says the FDA. The agency's revised letter puts the onus squarely on you, the healthcare provider, to "verify with the individual Original Equipment Manufacturers that their devices are compatible with the SS1E" and to evaluate the FDA's description of the system's "liquid chemical sterilant processing and rinse water element and determine how the device fits with [your] infection control programs."

Irene Tsikitas