An in vitro method for detecting off-target insertion of a nucleic acid region into the genome of a cell, the method comprising: (i) contacting the cell with a gene editing reagent and a donor nucleic acid molecule under conditions that allow for the generation of a double-stranded break at a predetermined genetic locus and insertion of all or part of the donor nucleic acid molecule into the genome DNA of the cells, (ii) collecting nucleic acid from the cell of (i) to generate a nucleic acid sample, (iii) fragmenting the nucleic acid in the nucleic acid sample thereby forming a plurality of fragmented genomic DNA segments, where at least one of the fragmented genomic DNA segments includes the inserted nucleic acid region; (iv) ligating both ends of the plurality of fragmented genomic DNA segments with a universal first adaptor thereby forming a plurality of universal adaptor fragmented genomic DNA segments; (v) contacting the plurality of universal adaptor fragmented genomic DNA segments with a primer complementary to the universal adaptor and a primer complementary to the nucleic acid region, wherein the primer complementary to the nucleic acid region is a 5'-phosphate primer; (vi) amplifying said nucleic acid region using a first polymerase chain reaction procedure thereby forming a plurality of amplified 5'-phosphate nucleic acid regions; (vii) ligating a second nucleic acid adaptor to said plurality of amplified 5'-phosphate nucleic acid regions thereby forming a plurality of adaptor nucleic acid regions; (viii) amplifying said plurality of adaptor nucleic acid regions using a second polymerase chain reaction procedure and a primer complementary to said second adaptor, thereby forming a plurality of amplified adaptor nucleic acid regions; (ix) attaching said plurality of amplified adaptor nucleic acid regions to a separation agent thereby forming a plurality of captured adaptor nucleic acid regions; and (x) sequencing said captured adaptor nucleic acid regions thereby detecting said nucleic acid region. (i) contacting the cell with a gene editing reagent and a donor nucleic acid molecule under conditions that allow for the generation of a double-stranded break at a predetermined genetic locus and insertion of all or part of the donor nucleic acid molecule into the genome DNA of the cells, (ii) collecting nucleic acid from the cell of (i) to generate a nucleic acid sample, (iii) fragmenting the nucleic acid in the nucleic acid sample thereby forming a plurality of fragmented genomic DNA segments, where at least one of the fragmented genomic DNA segments includes the inserted nucleic acid region; (iv) ligating both ends of the plurality of fragmented genomic DNA segments with a universal first adaptor thereby forming a plurality of universal adaptor fragmented genomic DNA segments; (v) contacting the plurality of universal adaptor fragmented genomic DNA segments with a primer complementary to the universal adaptor and a primer complementary to the nucleic acid region, wherein the primer complementary to the nucleic acid region is a 5'-phosphate primer; (vi) amplifying said nucleic acid region using a first polymerase chain reaction procedure thereby forming a plurality of amplified 5'-phosphate nucleic acid regions; (vii) ligating a second nucleic acid adaptor to said plurality of amplified 5'-phosphate nucleic acid regions thereby forming a plurality of adaptor nucleic acid regions; (viii) amplifying said plurality of adaptor nucleic acid regions using a second polymerase chain reaction procedure and a primer complementary to said second adaptor, thereby forming a plurality of amplified adaptor nucleic acid regions; (ix) attaching said plurality of amplified adaptor nucleic acid regions to a separation agent thereby forming a plurality of captured adaptor nucleic acid regions; and (x) sequencing said captured adaptor nucleic acid regions thereby detecting said nucleic acid region. <EOS>