The Pathology Company

RNA ISH (Ribonucleic acid in situ hybridization) assays are an ever-expanding application due to the ability to evaluate molecular targets with the added benefit of retaining tissue morphology. The rate limiting step in RNA ISH assays is the time consuming and error prone method of manually counting signal when reviewing under a microscope. The Aperio RNA ISH algorithm offers a reproducible, fast, and quantitative method of evaluating tissue samples which have been stained to detect RNA ISH signal. This single algorithm can be used on numerous tissue types for both single and dual-plex assays. Within this paper, we describe a validation study, which was performed in order to verify the correlation between the Aperio RNA ISH algorithm and the current gold standard method of manual interpretation. A total of 30 digital slides ranging in tissue source and assays types were scored manually by a scientist and the resulting data were correlated with scores obtained from the Aperio RNA ISH algorithm. In both modalities, the number of cells, count of signal within the cell, and signal in all tissue were recorded. The high level of correlation between the two methods (>R2 0.99) confirm that automated image analysis can be used as a fast and reproducible alternative to the traditional methods of manual interpretation.