In 2004, the first guideline report was published covering the rationale and strategy for conducting in vitro toxicity testing of tobacco smoke and to identify key procedures based upon internationally recognized guidelines, adapted to accommodate the nature and unique properties of tobacco smoke.

In 2018, the CORESTA In Vitro Toxicity Testing Sub-Group decided to review the 2004 guideline in order to: 1) re-evaluate the relevance of the initial rationale and strategy of in vitro testing of combustible tobacco products, 2) identify recent and comparable regulatory testing guidelines and examples in publications, and 3) provide a pragmatic summary of key features of each recommended assay.

The review effort revealed the continued usage and reference of the CORESTA in vitro test battery, especially where standardized and validated testing is required, upholding that the overall strategy and rationale remains valid and relevant. Sometimes these standardized testing results were supplemented with newer and exploratory in vitro assays. However, the in vitro tests recommended in 2004 continue to be used in a comparative product testing, such as to evaluate the biological impact of changes in ingredients or product designs against reference tobacco products as part of weight-of-evidence toxicity evaluation.

This report is an update of the 2004 report.