Modern random access analysers are playing a determining role in the productivity of clinical laboratories and their ability to offer clinicians an ever-wider range of tests with state-ofthe-art analytical performance. Assay sensitivity increasing and the number of on-board reagents expanding, however, the potential for interaction among and between samples, reagents and analyzer has increased, hence, the possibility for a negative impact on patient results. We here report on our brief to verify sample-tosample and reagent-to-reagent carry over for a total of 32 new reagents equating 32 x (31+ 54) x 2 or 5440 reagent combinations on the Abbott AEROSET® with confirmation of carry over on ARCHITECT® c8000 clinical chemisty analyzers.