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 inhibits 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 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 automate processing ccfDNA with the PreAnalytiX QIAsymphony PAXgene Blood ccfDNA Kit (CE-IVD) or process ccfDNA manually with the 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 QIAsymphony DSP DNA Mini and Midi Kits, or manually with the QIAamp DSP DNA Blood Mini Kit (See " The PAXgene Blood ccfDNA Tube (CE-IVD) with the QIAsymphony PAXgene Blood ccfDNA Kit (CE-IVD) and QIAsymphony instrument (CE-IVD) have been verified and validated as an integrated workflow.").
ccfDNA yields from plasma processed from blood collected into PAXgene Blood ccfDNA Tubes (CE-IVD) extracted with the QIAsymphony PAXgene Blood ccfDNA Kit (CE-IVD) or the QIAamp DSP Circulating Nucleic Acid Kit are similar to plasma from EDTA tubes separated directly after blood draw (See " Relative yield for ccfDNA from PAXgene Blood ccfDNA Tube (CE-IVD) plasma processed automated or manually compared to EDTA tube plasma at Day 0."). However, in contrast to unstabilized EDTA, blood drawn into PAXgene Blood ccfDNA Tubes have stable ccfDNA levels 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 cells lysing or undergoing apoptosis is prevented (See " Minimization of DNA release into plasma from blood samples stored in the PAXgene Blood ccfDNA Tube (CE-IVD).") and ccfDNA is preserved (See " Preservation of ccfDNA yield in plasma from blood samples stored in the PAXgene Blood ccfDNA Tube (CE-IVD).").
Genomic DNA in the nucleated cellular fraction is preserved and can be isolated with high purity, yield, and integrity (See " Yield, purity and integrity of gDNA from blood samples stored in the PAXgene Blood ccfDNA Tube (CE-IVD)."). 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 are compatible for downstream analytical PCR assays, including user-validated methylation-based PCR, and next-generation sequencing (NGS) molecular test methods (See " Quality Parameters demonstrate ccfDNA isolated from PAXgene Blood ccfDNA Tubes (CE-IVD) compatibility with NGS-based test methods.").