An inter-laboratory Mouse Lymphoma Assay (MLA) proficiency study was conducted by four member laboratories of the CORESTA Sub-Group In vitro Toxicity Testing (IVT). The study evaluated the proficiency of each participating laboratory in conducting the MLA and to determine the discriminatory power of each laboratory’s assay in relation to combustible tobacco products.

The lack of statistically significant findings between the responses induced by the test pieces across this study meant that the ranking of mutagenic potencies was not possible. The data however were used to calculate the minimal detectable differences (MDD) of each laboratory’s MLA.