Revisit the 21-day cumulative irritation test – statistical considerations

Abstract

The 21-day cumulative irritation test is widely used for evaluating the irritation potential of topical skin-care products. This test consists of clinician’s assessment of skin reaction of the patch sites and a classification system to categorize the test product’s irritation potential. A new classification system is proposed which enables us to control the estimation error and provides a statistical confidence with regard to the repeatability of the classification.

• Evaluation method
• irritation
• skin-care products

Acknowledgements

The authors thank Dr. Thomas J. Stephens for his valuable comments and suggestions.

Declaration of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article.