METHOD

A method for determining the presence, absence or amount of two or more target polynucleotides in a sample comprising additional components, the method comprising: (i) contacting the sample with a panel of two or more probes under conditions suitable for hybridisation of the target polynucleotides to the probes, wherein: (a) each probe comprises a non-hybridisation region and a hybridisation region that specifically hybridises to one of the target polynucleotides to form a hybridised probe; and (b) the hybridisation region of a probe of the panel comprises one or more non-natural nucleotides;(ii) contacting the sample prepared in step (i) with a transmembrane pore through which a single stranded polynucleotide but not a double stranded polynucleotide can pass and applying a potential difference to the transmembrane pore such that the hybridised probes in the sample interact with the pore; (iii) measuring current blockades having a duration within a defined window, wherein: (a) the oneor more non-natural nucle