The emergence of non-invasive disease assessment and progression monitoring has resulted in the development of many new cell-free DNA (cfDNA) assays. Challenges have emerged from this development including the extraction of cfDNA from biofluids such as blood, plasma and urine, which often yields very low quantities of highly-fragmented DNA. Assays for cfDNA are intended to identify genetic variants present at very low allelic frequencies, as low as 0.1% and beyond, which challenges the detection limits of many current technologies. High-throughput platforms such as NGS and qPCR give researchers greater power when profiling cfDNA samples, however further consideration must be given to sample variability, platform bias, and potential failure to detect biomarkers.   
   
Horizon has developed the cfDNA Reference Standard range to support the advancement and continued evaluation of cfDNA workflows across a range of platforms including NGS, ddPCR and qPCR. These standards are manufactured from engineered human cancer cell lines, thereby providing a consistent and renewable resource for cfDNA workflow evaluation.   
   
Horizon’s cfDNA Reference Standards are fragmented to an average size of 160bp to resemble cfDNA extracted from human plasma (see Figure 1). The reference standards are provided in a set containing fragmented DNA in a range of low allelic frequencies (0.1% to 5%), with a matched wild type. Key applications of the reference standards include defining key characteristics for assays and platforms including the limit of detection, sensitivity, specificity, and standard curves.   
   
cfDNA Reference Standards are available in Multiplex and Singleplex sets, providing an essential laboratory input for analysis of workflows right the way through to bioinformatics.