Most techniques, including NOIR-SS, cannot discriminate true mutations from variants introduced by DNA damage. In contrast, duplex sequencing  can discriminate variants present in both strands (mutations) of the DNA and those present in only a single strand (DNA damage). Therefore, comprehensive analysis of cfDNA from patients with cancer using duplex sequencing would be highly beneficial for understanding the origin of variants. However, duplex sequencing is not suitable for diagnostic use, because it requires a vast amount of DNA . Generally, it is more important to discriminate mutations occurring in the tumor tissue from mutations occurring in normal tissue, than it is to discriminate between genuine mutations and DNA damage.