FRET-based analytes detection and related methods and systems are described where a pair of FRET labeled primers and/or oligonucleotides are used that are specific for target sequences located at a distance up to four time the Forster distance of the FRET chromophores presented on the FRET labeled primers and/or oligonucleotides one with respect to the other in one or more polynucleotide analyte; in particular the pair of FRET labeled primers and/or oligonucleotides is combined with a sample and subjected to one or more polynucleotide amplification reactions before measuring FRET signals from at least one FRET chromophore.