RT Journal Article SR Electronic T1 Idylla EGFR assay on extracted DNA: advantages, limits and place in molecular screening according to the latest guidelines for non-small-cell lung cancer (NSCLC) patients JF Journal of Clinical Pathology JO J Clin Pathol FD BMJ Publishing Group Ltd and Association of Clinical Pathologists SP jclinpath-2022-208325 DO 10.1136/jcp-2022-208325 A1 Khalifa, Emmanuel A1 Chapusot, Caroline A1 Tournier, Benjamin A1 Sentis, Julie A1 Marion, Estelle A1 Remond, Alicia A1 Aubry, Manon A1 Pioche, Célia A1 Bergeron, Anthony A1 Primois, Charlotte A1 Blanchard, Larry A1 Millière, Alice A1 Boucheix, Marlène A1 Léger, Yannick A1 Bairrao, Marine A1 Brouste, Véronique A1 Martin, Laurent A1 Soubeyran, Isabelle YR 2022 UL http://jcp.bmj.com/content/early/2022/07/11/jcp-2022-208325.abstract AB Aims Idylla epidermal growth factor receptor (EGFR) is a fast and fully automated mutation assay that is easy to implement. However, under the Biocartis-recommended technical conditions, tissue sections are directly introduced into the cartridge, at the risk of exhausting the tumour sample. In this study, we evaluate the performance of Idylla EGFR on extracted DNA and discuss its place within the global non-small-cell lung cancer (NSCLC) screening strategy.Methods 577 comparative tests between Idylla EGFR on extracted DNA and next-generation sequencing (NGS) were performed across two centres.Results Preanalytical thresholds were established (20% tumour cell content, 50 ng DNA input) and challenged prospectively in routine practice. 16.8% of samples referred for screening were considered non eligible for Idylla EGFR testing. Due to discordant by design cases, Idylla EGFR sensitivity was 86.9% for currently actionable EGFR mutations. Idylla EGFR specificity was 100% in first-line screening. NGS was always feasible on the same DNA.Conclusion Idylla EGFR on extracted DNA is feasible and enables tumour material to be saved compared with tissue section use. It is not necessary to replace the analytical thresholds of the Biocartis algorithm. Due to both the limits of the mutational repertoire and the high increase of targetable genes in NSCLC, the use of Idylla EGFR should be restricted to clinical emergency situations accompanied by NGS.All data relevant to the study are included in the article or uploaded as online supplemental information.