A method of detecting the presence or absence of a target nucleic acid variant in a sample, wherein a target nucleic acid may occur in at least two variants, the method comprising (a) providing at least one labeled oligonucleotide comprising a first label, which first label comprises at least one light emitting moiety and wherein at least a subsequence of the labeled oligonucleotide is sufficiently complementary to at least a subsequence of the target nucleic acid such that the labeled oligonucleotide hybridizes with the target nucleic acid under a selected condition; (b) providing at least one soluble light emission modifier, which, when the modifier non-covalently binds double stranded DNA incorporating the labeled oligonucleotide, quenches light emission from the first label and does not significantly quench the light emission of the first label in the presence of the soluble light emission modifier when the labeled oligonucleotide is single-stranded; (c) amplifying the target nucleic acid in the sample in the presence of the labeled oligonucleotide and the soluble light emission modifier in an amplification reaction under the selected condition such that the labeled oligonucleotide is extended to produce a first double-stranded labeled amplicon incorporating the labeled oligonucleotide, wherein the first double-stranded labeled amplicon has a different melting temperature depending on which of the at least two target nucleic variants are amplified; (d) detecting the melting temperature of the double-stranded labeled amplicon dissociated into two single strands by monitoring the signal of the label under changing temperature; and (e) correlating the melting temperature of the double-stranded labeled amplicon to the presence of one of the at least two target variants, thereby detecting the presence or absence of a target nucleic acid variant in a sample. (a) providing at least one labeled oligonucleotide comprising a first label, which first label comprises at least one light emitting moiety and wherein at least a subsequence of the labeled oligonucleotide is sufficiently complementary to at least a subsequence of the target nucleic acid such that the labeled oligonucleotide hybridizes with the target nucleic acid under a selected condition; (b) providing at least one soluble light emission modifier, which, when the modifier non-covalently binds double stranded DNA incorporating the labeled oligonucleotide, quenches light emission from the first label and does not significantly quench the light emission of the first label in the presence of the soluble light emission modifier when the labeled oligonucleotide is single-stranded; (c) amplifying the target nucleic acid in the sample in the presence of the labeled oligonucleotide and the soluble light emission modifier in an amplification reaction under the selected condition such that the labeled oligonucleotide is extended to produce a first double-stranded labeled amplicon incorporating the labeled oligonucleotide, wherein the first double-stranded labeled amplicon has a different melting temperature depending on which of the at least two target nucleic variants are amplified; (d) detecting the melting temperature of the double-stranded labeled amplicon dissociated into two single strands by monitoring the signal of the label under changing temperature; and (e) correlating the melting temperature of the double-stranded labeled amplicon to the presence of one of the at least two target variants, thereby detecting the presence or absence of a target nucleic acid variant in a sample.