Molecular pathology is continuously evolving and laboratories are challenged to implement tests accurately prior to administration of targeted therapies. External quality assessment (EQA) programs revealed method-specific problems for laboratories who switched methods, and a good adherence to guidelines during method validation/verification in the USA. This study evaluated current guideline adherence in Europe and experienced hurdles during test, marker or sample implementation. EQA participants from the European Society of Pathology were invited to complete an electronic survey if they: (i) recently changed their assay, (ii) implemented PD-L1 analysis, (iii) or introduced analysis of circulating tumor DNA. In total, survey data from 54 laboratories was analyzed. The majority of laboratories implemented a written procedure for validation (68.5%) or verification (59.3%), in 53.7% and 44.4% cases based on standards or available literature. For 20.4% of respondents, a specific guideline was not available yet for their test strategy. Method