UMIs are appropriate for applications that produce high levels of duplicates. For, example, when sequencing low input cfDNA to detect very low frequency variants, ultra-deep sequencing is necessary (20, 000 – 30, 000 raw read depth). This results in high duplicates (~90%). When duplicates are removed using the UMI approach this will result in a consensus read depth of 2,000 to 3, 000x. Cell3™ Target’s built in UMIs enables a single workflow for all sample types and tests allowing confident and sensitive calling of mutations down to 0.1% VAF and from as little as 10ng ctDNA input. This allows you to choose to use them or not without any penalties in your resulting data.
UMIs are not necessary when sequencing at lower depths, e.g., sequencing gDNA from whole blood or from tissue samples (FFPE or FF). This is because the proportion of duplicates is much lower (approx. 4% when sequencing gDNA at 100x depth for the ExomeCG).