PRC - patch ready cells are cryopreserved at a highly functional state. The PRCs can be used in patch clamp assays instantly after thawing without any prior cultivation to increase the flexibility and reproducibility of the assay. The Comprehensive in vitro Proarrhythmia Assay (CiPA) comprise a panel of six cardiac ion channels to replace the insuffi cient testing on hERG blockage and QT prolongation according to ICH S7A & S7B. Recombinant cell lines stably expressing these ion channels have been developed and validated by B’SYS to assess the cardiac risk of drug candidates.