The validation of the methods for the detection and quantification of genetically modified organisms (GMOs) is required as a part of genetically modified food and feed authorization in the European Union (EU). Each validated method must meet the minimum performance requirements for GMO testing methods defined at the EU level. This ensures that the National Reference Laboratories (NRLs), which act as the official control laboratories, use reliable, precise, and robust GMO detection and quantification methods. The NRLs demonstrate their competence by obtaining and maintaining accreditation according to the ISO/IEC 17025 standard. The technical requirements of this standard, primarily related to the tests performed in the laboratory, include all factors that determine the required correctness and reliability of each implemented method. In the process of GMO authorization, applicants can submit any method that fulfills the validation criteria. In turn, the validated methods for the detection and
quantification of different GM events in the same species often vary regarding the reference gene assay and PCR conditions. This results in the need of multiple PCR analysis of samples with various GM events. Harmonization
of the method validation parameters allows for the detection of different GM events in single PCR run, which simplify the routine laboratory work and decrease the costs of performed tests, therefore improving the efficiency
of the official control of the EU market. This is particularly important as the number of authorized GMOs in EU for food and feed is continuously growing. In this study, we report successful quantitative real-time PCR method
harmonization for 8 of the 10 GM maize events.