Evaluation of five cell-free DNA isolation kits for plasma

Abstract

Cell-free DNA (cfDNA) has been widely used in prenatal test and cancer diagnosis nowadays. The cost- and time-effective isolation kits are needed especially in large-scale clinical application. Here, we compared three domestic kits: VAHTS Serum/Plasma Circulating DNA kit (VZ), MagPure Gel Pure DNA mini kit (MG) and Serum/Plasma Circulating DNA Kit (TG), together with QIAamp Circulating Nucleic Acid Kit (QC) and QIAamp DNA Blood Mini Kit (QD) in cfDNA isolation. cfDNA was isolated from the pooled samples with spike-in fragments, qPCR was conducted to quantify the spike-in fragments recovery. The results indicated that all of the five kits could isolate cfDNA with different efficiency. The VZ kit had an efficiency as high as 90 percent, which is comparable to QC kit. The libraries were constructed using the isolated cfDNAs, quantified by Qubit and analyzed by 2100 bioanalyzer. Both showed the libraries were qualified. Finally, cffDNAs were detected by qPCR targeting SRY gene using libraries from pregnant women bearing male fetuses. All five kits could isolate cffDNAs that could be detected by qPCR. Our results provided more choices in wide-scale clinical application of cfDNA-based non-invasive genetic tests.