Confirmation of at least one amplified nucleic acid target sequence (target sequence) during a duplication reaction in a collective and continuous reaction setup containing a reaction mixture comprising - at least one target sequence to be verified, - at least two target sequence-specific primers (P1, P2, P 1-n) being suitable for amplification of the at least one target sequence, - at least one labelled target sequence-specific flap endonuclease probe (FEN probe FEN1, FEN 1-n), the at least one FEN probe comprising • a target sequence-specific 3'-sequence which is complementary to a sequence fragment of the at least one target sequence within a region being restricted on the target sequence by the at least first primer and the at least second primer, • a protective group at the 3'-end of the target sequence-specific 3'-sequence, and • a target sequence-unspecific 5'-sequence which is labelled at its 5'-end with one hapten of a specific hapten pair, and - at least one artificial matrix sequence, - at least one further primer, the further primer being complementary to a sequence fragment of the counter strand of the at least one artificial matrix sequence, and/or - at least one FEN enhancer oligonucleotide (ENH 1-n) the confirmation assay comprises per cycle of the duplication reaction the steps of - hybridisation of the target sequence-specific 3'-sequence of the at least one FEN probe to a complementary sequence of the at least one target sequence to be verified, - cleavage of the at least one FEN probe, - obtaining at least one free 5'-cleavage product (S 1-n) each comprising the target sequence-unspecific 5'-sequence, - hybridisation of the at least one 5'-cleavage product (S 1-n) of the at least one FEN probe to a complementary sequence of the at least one artificial matrix sequence, - amplification of the at least one artificial matrix sequence using the at least one 5'-cleavage product (S 1-n) of the at least one FEN probe and the at least one primer, and - optionally, labelling of the at least one artificial matrix sequence during amplification by the at least one 5'-cleavage product (S 1-n) of the at least one FEN probe. - at least one target sequence to be verified, - at least two target sequence-specific primers (P1, P2, P 1-n) being suitable for amplification of the at least one target sequence, - at least one labelled target sequence-specific flap endonuclease probe (FEN probe FEN1, FEN 1-n), the at least one FEN probe comprising • a target sequence-specific 3'-sequence which is complementary to a sequence fragment of the at least one target sequence within a region being restricted on the target sequence by the at least first primer and the at least second primer, • a protective group at the 3'-end of the target sequence-specific 3'-sequence, and • a target sequence-unspecific 5'-sequence which is labelled at its 5'-end with one hapten of a specific hapten pair, and • a target sequence-specific 3'-sequence which is complementary to a sequence fragment of the at least one target sequence within a region being restricted on the target sequence by the at least first primer and the at least second primer, • a protective group at the 3'-end of the target sequence-specific 3'-sequence, and • a target sequence-unspecific 5'-sequence which is labelled at its 5'-end with one hapten of a specific hapten pair, and - at least one artificial matrix sequence, - at least one further primer, the further primer being complementary to a sequence fragment of the counter strand of the at least one artificial matrix sequence, and/or - at least one FEN enhancer oligonucleotide (ENH 1-n) - hybridisation of the target sequence-specific 3'-sequence of the at least one FEN probe to a complementary sequence of the at least one target sequence to be verified, - cleavage of the at least one FEN probe, - obtaining at least one free 5'-cleavage product (S 1-n) each comprising the target sequence-unspecific 5'-sequence, - hybridisation of the at least one 5'-cleavage product (S 1-n) of the at least one FEN probe to a complementary sequence of the at least one artificial matrix sequence, - amplification of the at least one artificial matrix sequence using the at least one 5'-cleavage product (S 1-n) of the at least one FEN probe and the at least one primer, and - optionally, labelling of the at least one artificial matrix sequence during amplification by the at least one 5'-cleavage product (S 1-n) of the at least one FEN probe.