Figure 2.

Design of experiment to test extraction methods' abilities to detect low concentrations of short DNA fragments in urine. Ten copies per milliliter of 40-nt target were spiked into urine, extracted, and detected by real-time quantitative PCR. PCR was performed in triplicate, except for hybridization, where the entire output was analyzed in a single PCR well. PCR was considered positive if >500 relative fluorescence units (RFUs) after 45 amplification cycles. The dashed line indicates an example RFU threshold for determination of the PCR quantification cycle. n = 6.