Performance comparison of blood collection tubes as liquid biopsy storage system for minimizing cfDNA contamination from genomic DNA.

The ratio of target cfDNA in total plasma is low. The abundant gDNA background resulting from blood cell lysis caused by improper operation has become a major obstacle to accurately measure cfDNA. In this study, we investigated the storage capacity of three blood cell collection tubes (BCTs) in the prevention of genomic DNA contamination caused by white blood cell rupture and evaluated their performance when they were utilized combining with highly sensitive mutation detection technology. Blood samples were drawn from six healthy blood donors and stored in three types of BCTs (BD K2 -EDTA tube, Roche tube, and Streck tube). Plasma samples were isolated at specific time points (day 0, day 3, day 7, and day 14) for content analysis. Roche BCT was more capable for preventing cfDNA contamination caused by white blood cell disruption within 14 days, comparing with BD K2 -EDTA tube and Streck tube. Severe white blood cell lysis and gDNA contamination were found in the BD tube. The impacts of Roche and Streck tubes on the quantity and complexity of next-generation sequencing (NGS) libraries did not differ significantly within 3 days, satisfying most of our daily demands. In addition, the rupture of WBC was not synchronized with hemolysis in BCTs. This study showed that capacities of blood collection tubes differed considerably in preservation of blood samples. Therefore, suitable blood collection devices should be selected to minimize gDNA contamination and to standardize blood samples processing for achieving more accurate and reliable clinical analysis of cfDNA.