PAXgene Blood ccfDNA Tubes (CE-IVD) simplify the collection and processing of whole blood for subsequent purification of circulating, cell-free DNA (ccfDNA) from plasma and genomic DNA (gDNA) from the nucleated cellular fraction. The tube additive is non-crosslinking, free of formaldehyde-releasing substances, stabilizes blood cells and prevents prevent apoptosis.
Using PAXgene Blood ccfDNA Tubes (CE-IVD) for whole blood collection, storage and transport helps prevent the release of intracellular DNA into plasma (see " PAXgene Blood ccfDNA stabilization minimizes hemolysis compared to alternative solutions" and " PAXgene Blood ccfDNA stabilization reagent helps prevent release of gDNA into plasma").
Plasma generated from whole blood collected into PAXgene Blood ccfDNA Tubes (CE-IVD) can be used to process ccfDNA automated with the PreAnalytiX QIAsymphony PAXgene Blood ccfDNA Kit (CE-IVD) or the QIAGEN QIAamp DSP Circulating Nucleic Acid Kit. The nucleated cellular fraction or buffy coat remaining after removal of the plasma can be processed for gDNA automated with the QIAGEN QIAsymphony DSP DNA Mini and Midi Kits or manually with the QIAGEN QIAamp DSP DNA Blood Mini Kit (See "Figure 2").
ccfDNA yields from plasma processed from blood collected into PAXgene Blood ccfDNA Tubes are similar to plasma from EDTA tube separated directly after blood draw (See "Figure 3"). But in contrast to unstabilized EDTA, within blood drawn into PAXgene Blood ccfDNA Tubes ccfDNA levels are stable for up to 10 days at temperatures up to 25°C, 7 days at temperatures up to 30°C or 3 days at temperatures up to 37°C (Note: Do not store blood-filled tubes below 2°C), because DNA release from lysing or apoptotic cells is prevented (See "Figure 4") and ccfDNA is preserved (See "Figure 5"). Genomic DNA in the nucleated cellular fraction is preserved and can be isolated with high purity, yield and integrity (See "Figure 6"). Thus, blood samples can be transported and stored within the specified temperature and duration to process plasma later (see technical note ´Sample Transportation Study (Summer Profile)´).
Plasma and nucleated cellular fraction generated from whole blood collected into PAXgene Blood ccfDNA Tubes are stable at room temperature for at least 3 days, at refrigerated temperature for at least 7 days and can be stored for long-term frozen at -20°C or -80°C (for latest update see technical note ´Plasma and Nucleated Cellular Fraction Stability Study´).
Pre-analytical steps including handling, storage, processing and documentation of verification and validation studies of PAXgene Blood ccfDNA Tube were conducted in accordance with ISO 20186-2:2019 and ISO 20186-3:2019: Molecular in vitro diagnostic examinations — Specifications for pre-examination processes for venous whole blood — Part 2: Isolated genomic DNA and — Part 3: Isolated circulating cell free DNA from plasma. Stabilization characteristics have been shown to be robust against elevated level of endogenous, potentially interfering substances, underfilling and inappropriate mixing (see technical note ´ Tube Robustness Study´ ).
Both ccfDNA and gDNA yields are high-quality and can be used for downstream analytical assays, including but not limited to PCR-based assays, methylation assays, and next-generation sequencing (NGS) (See "Figure 7").