A loop mediated isothermal amplification (LAMP) method, comprising synthesizing a nucleic acid sequence from a template nucleic acid sequence in a reaction mixture comprising (i) a first inner primer (FIP) nucleotide sequence and a second inner primer (BIP) nucleotide sequence, (ii) a first outer primer (F3) nucleotide sequence and a second outer primer (B3) nucleotide sequence, wherein said F3 nucleotide sequence and/or said B3 nucleotide sequence comprises one or more locked nucleic acid (LNA) nucleotides which are located within the first third of said F3 nucleotide sequence or said B3 nucleotide sequence, respectively, wherein said first third is the first third of a nucleotide sequence in 5'- to 3'-orientation, (iii) a DNA polymerase catalyzing a strand-displacement-type reaction of synthesizing a complementary nucleic acid strand from said template nucleic acid, and (iv) nucleotides serving as substrates for said DNA polymerase at such a temperature that at least FIP nucleotide sequence and BIP nucleotide sequence can form stable base pairing with its complementary nucleotide sequences comprised by said template nucleic acid while the DNA polymerase activity can be maintained, thereby synthesizing a nucleic acid sequence. synthesizing a nucleic acid sequence from a template nucleic acid sequence in a reaction mixture comprising (i) a first inner primer (FIP) nucleotide sequence and a second inner primer (BIP) nucleotide sequence, (ii) a first outer primer (F3) nucleotide sequence and a second outer primer (B3) nucleotide sequence, wherein said F3 nucleotide sequence and/or said B3 nucleotide sequence comprises one or more locked nucleic acid (LNA) nucleotides which are located within the first third of said F3 nucleotide sequence or said B3 nucleotide sequence, respectively, wherein said first third is the first third of a nucleotide sequence in 5'- to 3'-orientation, (iii) a DNA polymerase catalyzing a strand-displacement-type reaction of synthesizing a complementary nucleic acid strand from said template nucleic acid, and (iv) nucleotides serving as substrates for said DNA polymerase (i) a first inner primer (FIP) nucleotide sequence and a second inner primer (BIP) nucleotide sequence, (ii) a first outer primer (F3) nucleotide sequence and a second outer primer (B3) nucleotide sequence, wherein said F3 nucleotide sequence and/or said B3 nucleotide sequence comprises one or more locked nucleic acid (LNA) nucleotides which are located within the first third of said F3 nucleotide sequence or said B3 nucleotide sequence, respectively, wherein said first third is the first third of a nucleotide sequence in 5'- to 3'-orientation, (iii) a DNA polymerase catalyzing a strand-displacement-type reaction of synthesizing a complementary nucleic acid strand from said template nucleic acid, and (iv) nucleotides serving as substrates for said DNA polymerase at such a temperature that at least FIP nucleotide sequence and BIP nucleotide sequence can form stable base pairing with its complementary nucleotide sequences comprised by said template nucleic acid while the DNA polymerase activity can be maintained, thereby synthesizing a nucleic acid sequence. <EOS>