Fig. 3From: Towards standardization of next-generation sequencing of FFPE samples for clinical oncology: intrinsic obstacles and possible solutionsThe counts of mutations detected in various ranges of allele frequencies. Samples with pre-normalization library concentrations as low as 1.5 ng/μl were shown to yield substantial amounts of presumably artifactual variants with high prevalence in the sequencing reads. These mutations could not be filtered out by using preset frequency thresholdsBack to article page