Collaborative trial to assess the performance of digital PCR in the field of GMO analysis using an artificial sample material

Digital PCR promises absolute quantification of amplifiable nucleic acids molecules. In consequence, results should be comparable, irrespective of the analysing laboratory and the equipment used. To assess this claim, we used a multitarget DNA molecule (amplicon) encoding for eight transgene soy traits and the lectin soy reference gene. This multitarget amplicon was analysed by seven European laboratories by duplex digital PCR assays. The results showed that absolute measurements of target copy number range revealed high variation. Nevertheless, the measured proportion of the transgene target sequences to the lectin reference gene of the amplicon was in most cases close to 1:1. Digital PCR seems to produce interlaboratory highly reproducible results of relative quantification. Care has to be taken to assess the performance of the applied PCR system. For this purpose, multitarget amplicons may be a valuable amendment to reference material gained from plant material, particularly in cases where reference material is unavailable.