title: Comparative analysis of circulating tumor DNA stability In K3EDTA, Streck, and CellSave blood collection tubes.
abstract: OBJECTIVE
  Optimal conditions for blood collection for circulating tumor DNA (ctDNA) are still being developed. Although both Streck and EDTA tubes are commonly used, their ability to stabilize ctDNA as a function of time and temperature post-collection has not been thoroughly studied. Additionally, the potential utility of CellSave tubes (commonly used for circulating tumor cell) for ctDNA measurements has not been studied.
  
  
  METHODS
  Blood was collected into Streck, EDTA, and CellSave tubes from ten patients with metastatic breast cancer enrolled in the MI-ONCOSEQ tumor sequencing program at the University of Michigan and kept either on ice or at room temperature until plasma isolation. Plasma was processed after 2, 6, and 48h post-collection. We used droplet digital PCR (ddPCR) to quantify plasma ctDNA and wild-type DNA for six patients who had tumor tissue mutations represented in commercially available ddPCR assays.
  
  
  RESULTS
  ctDNA abundance was similar and stable for up to 6h in all tube types, and there was no effect of storage temperature on the yield for Streck and EDTA tubes. After 48h, however, one out of four patients with detectable ctDNA showed a ~50% decline in ctDNA in the EDTA tube, and three out of six patients showed a 2-3-fold increase in wild-type DNA in the EDTA tube.
  
  
  CONCLUSIONS
  Streck, EDTA, and CellSave tubes showed similar performance in preserving ctDNA for up to 6h before plasma isolation. Streck and CellSave tubes more consistently stabilized ctDNA and wild-type DNA at 48h than EDTA tubes.
authors.affiliation: Department of Internal Medicine, Division of Hematology/Oncology, University of Michigan, Ann Arbor, MI, USA.
authors.forename: Qing
authors.initials: Q
authors.lastname: Kang
authors.affiliation: Department of Internal Medicine, Division of Hematology/Oncology, University of Michigan, Ann Arbor, MI, USA.
authors.forename: N Lynn
authors.initials: NL
authors.lastname: Henry
authors.affiliation: Department of Internal Medicine, Division of Hematology/Oncology, University of Michigan, Ann Arbor, MI, USA.
authors.forename: Costanza
authors.initials: C
authors.lastname: Paoletti
authors.affiliation: Department of Biostatistics, School of Public Health, University of Michigan, Ann Arbor, MI, USA.
authors.forename: Hui
authors.initials: H
authors.lastname: Jiang
authors.affiliation: Michigan Center for Translational Pathology, University of Michigan, Ann Arbor, MI, USA.
authors.forename: Pankaj
authors.initials: P
authors.lastname: Vats
authors.affiliation: Michigan Center for Translational Pathology, University of Michigan, Ann Arbor, MI, USA; Department of Pathology, University of Michigan, Ann Arbor, MI, USA; Department of Urology, University of Michigan, Ann Arbor, MI, USA; Comprehensive Cancer Center, University of Michigan Health System, Ann Arbor, MI, USA; Howard Hughes Medical Institute, Ann Arbor, MI, USA.
authors.forename: Arul M
authors.initials: AM
authors.lastname: Chinnaiyan
authors.affiliation: Department of Internal Medicine, Division of Hematology/Oncology, University of Michigan, Ann Arbor, MI, USA.
authors.forename: Daniel F
authors.initials: DF
authors.lastname: Hayes
authors.affiliation: Department of Internal Medicine, Division of Hematology/Oncology, University of Michigan, Ann Arbor, MI, USA; Department of Epidemiology, School of Public Health, University of Michigan, Ann Arbor, MI, USA.
authors.forename: Sofia D
authors.initials: SD
authors.lastname: Merajver
authors.affiliation: Department of Internal Medicine, Division of Hematology/Oncology, University of Michigan, Ann Arbor, MI, USA.
authors.forename: James M
authors.initials: JM
authors.lastname: Rae
authors.affiliation: Department of Internal Medicine, Division of Hematology/Oncology, University of Michigan, Ann Arbor, MI, USA; Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA; Center for Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI, USA; Biointerfaces Institute, University of Michigan, Ann Arbor, MI, USA. Electronic address: mtewari@med.umich.edu.
authors.forename: Muneesh
authors.initials: M
authors.lastname: Tewari
mesh_terms: D004273:DNA, Neoplasm / Q000097:blood*; D004492:Edetic Acid / Q000737:chemistry*; D006801:Humans; D013048:Specimen Handling / Q000295:instrumentation*
chemical_list: D004273:DNA, Neoplasm; D004492:Edetic Acid
keywords: CellSave; Circulating tumor DNA; Droplet digital PCR; Streck BCT