The Sterilization Packaging Manufacturers Council (SPMC) is addressing a number of questions presented to them during their February 2008 Webcast, “Understanding the Nuances of ISO 11607.” You may also find a complete list of questions and answers at the SPMC Web site at www.sterilizationpackaging.org [3], and at www.pmpnews.com [4].
And if you think of another question, please feel free to submit it to PMP News through Editor Daphne Allen at daphne.allen@cancom.com [5].
If you have a sterile fluid pathway, is this considered your sterile barrier system (SBS)? What would you suggest for validation of this SBS? Is outer packaging considered protective?
The following response was provided by Mike Scholla, Senior Consultant for DuPont, PMP News Editorial Advisory Board member, and convener of ISO TC198 WG7 group, which wrote and maintains responsibility for revising ISO 11607.
A sterile fluid path is a special case when it comes to a sterile barrier system, which is why there is a specific definition in ISO 11607. In a sterile fluid path system, fluids flow through a lumen; the critical characteristic is that the inside of the tube is sterile. This is in contrast to a typical medical device, where is it critical that the outside of the instrument is sterile. The sterility of the sterile fluid path system is maintained by the closure system of the fluid path, and it must be demonstrated that the closure system maintains sterility until point of use. Sterilization validation is usually conducted by exposure to an aerosol of spores followed by sterility testing of the lumen.
As many sterile fluid path systems are packaged in pouches, a common sterile barrier system, it is important to determine in each case what is providing the sterile barrier and to make sure that the package is labeled accordingly. Without such labeling, a user may assume that the pouch is providing the sterile barrier. If the sterile fluid pathway is labeled as such, then the pouch enclosing it may be considered protective packaging and validated as part of the packaging system.
When doing a test method validation, how do you know what the acceptable results are?
The acceptable results are relative to your test method and your specifications. For variable data, the results would be gauge repeatability and reproducibility (R&R) percentages per testing equipment. For attribute data, this could be based on confidence limits set by your company’s risk policy.
Percent R&R are common statistical references with the following ranges:
- 0–10% of tolerance—typically acceptable.
- 10–30% of tolerance—can be acceptable with rationale or justification.
- >30% of tolerance—typically unacceptable.
Other acceptance criteria should be based on your company’s risk policy and the relationship to specifications, if not already defined in a standard test method.
If a test method is validated (accuracy, precision, repeatability defined), does it need to be verified every time the test is run? For example, for the dye-penetration test, I validated it for a 0.002-in. channel leak. Do I need to prove it again every time I run the test?
No, you do not have to perform a test method validation every time a test is run. You would consider redoing a test method validation if you have a significant change in the method.
In the case of the dye test, while it is not required to prove it again every time, you may want to verify the sensitivity of the dye solution with every new batch by testing it with a known 0.002-in. channel leak or by controlling the production of the solution to maintain a high level of assurance of repeatability.
