Standard test methods often leave passing criteria undefined, allowing flexibility but requiring careful consideration to ensure meaningful results. This flexibility allows clients to establish their own thresholds based on product requirements, regulatory considerations, and market expectations. However, determining what constitutes “passing” is not always straightforward. Several key factors should guide this process, helping ensure consistent and meaningful results.

Reproducibility as a Foundation for Passing Criteria
One common approach is to focus on reproducibility between laboratories. This piece of criteria ensures that a technology or treatment performs consistently, regardless of where the testing occurs. For example, a 90% reduction threshold is often used in antimicrobial testing, especially with plate count enumeration methods. At this level, reproducible results can typically be achieved, making it a practical and widely accepted benchmark for passing criteria. This threshold provides confidence that a sample is either effectively treated or that the technology is robust enough to deliver reliable performance.

Statistical Differentiation Between Treated and Untreated Samples
Another way to define passing criteria is through statistical significance. Test methods like IACM 0712 rely on measurable differences between treated and untreated samples to confirm the efficacy of a technology. This approach goes beyond simple percentages, emphasizing clear and consistent differentiation as the standard for success. It’s particularly valuable in ensuring that results are meaningful and that claims are backed by strong statistical evidence.

Correlating Test Methods to Real-World Performance
For some test methods, passing criteria can be linked to real-world performance by correlating laboratory results with human assessments. For example, ISO 17299-2 includes correlations between lab-based odor control measurements and human odor panel thresholds, offering insight into how a product might perform in everyday use.

Similarly, IAC has developed preliminary correlations for AATCC TM211, presented at the 2023 AATCC Textile Discovery Summit. While correlations are not yet available for newer methods like IACM 0712, they represent an essential step in validating test results for real-world application.

Legal and Regulatory Considerations
From a legal perspective, reproducible differentiation between treated and untreated samples is often sufficient to support claims. However, this simplicity is accompanied by challenges in ensuring that claim language aligns with regulatory guidelines. Misinterpreting or overstating results can lead to compliance issues, underscoring the importance of clear, accurate communication when defining passing criteria and acceptable claims language.

Balancing Flexibility and Rigor
The lack of predefined passing criteria in standard test methods can be an advantage, offering flexibility to tailor thresholds to specific technologies or market needs. However, this flexibility requires careful planning and consideration to ensure that results are not only reproducible but also relevant and meaningful in real-world contexts. Whether focusing on reproducibility, statistical significance, or real-world correlations, passing criteria play a critical role in validating product performance and supporting claims.

Contact us to learn about antimicrobial and odor control standardized test methods and how the IAC can help you achieve your goals.