It is challenging to identify rare variants accurately using standard NGS methods with a mutation rate of (10 to 10). Errors that happen early during sample preparation can be detected as rare variants. An example of such errors is C>A/G>T transversion, detected in low frequencies using deep sequencing or targeted capture data and arising due to DNA oxidation during sample preparation. These types of false-positive variants are filtered out by the duplex sequencing method since mutations need to be accurately matched in both strands of DNA to be validated as true mutations. Duplex sequencing can theoretically detect mutations with frequencies as low as 10 compared to the 10 rate of standard NGS methods.