Figure 1.
DNA recovery from urine is dependent on both extraction method and target fragment length. A: To evaluate the length dependence of urine cfDNA extraction methods, synthetic targets of various lengths (25, 40, 80, and 150 nt) were spiked into urine at 104 copies/mL before extraction. The dashed line indicates an example relative fluorescence unit (RFU) threshold for determination of the PCR quantification cycle. B: Percentage recoveries are given. Results of extraction no template controls are given in Supplemental Table S1. *Wizard resin/guanidinium thiocyanate (Wizard/GuSCN) samples were adjusted to pH 6 and spiked with 1000 ng/mL background DNA. Data are expressed as means ± SD (B). n = 3 (B). n/a, indicates 25-nt fragment not tested for QIAamp and MagMAX; qPCR, real-time quantitative PCR.