Quality assessment of blood collection tubes by testing performance characteristics at the end of the tubes shelf life

The analysis of circulating cell-free DNA (ccfDNA) from blood has become routine in prenatal testing and is expanding in cancer diagnosis and therapy monitoring. Laboratories performing these tests require the implementation of standardized preanalytical procedures for sample collection and stabilization, transport, plasma processing, and ccfDNA extraction to obtain reliable results.

Blood collection and stabilization tubes for ccfDNA testing help prevent the release of genomic DNA from white blood cells into the plasma during blood storage and transport. The decision to use a specific blood collection tube is often based on the performance in downstream assays. In addition to compatibility with downstream assays, consistent performance over the shelf life of the blood collection tube is required.

This study compared the performance of blood collection tubes based on non-crosslinking and formaldehyde-releasing stabilization technologies at the end of each products shelf life.

Blood from 20 consented, healthy donors was collected into PAXgene Blood ccfDNA* (PreAnalytiX) Tubes and Streck Cell-Free DNA BCT (Streck) tubes which were close to their expiry date. Sheared DNA containing EGFR mutations was spiked into a subset of samples after blood draw. Plasma from paired tubes was either generated directly or after blood storage for 7 days at 30°C. Automated ccfDNA extraction was performed on the QIAsymphony (QIAGEN) using tube-specific kits and protocols. ccfDNA yield and EGFR mutations were analyzed by qPCR and ccfDNA fragment distribution was assessed using the BioAnalyzer (Agilent).

The reagent in the PAXgene Blood ccfDNA Tube efficiently stabilized blood for ccfDNA detection with consistent performance over the product’s shelf life. Stabilization reagents, which have the potential to chemically modify ccfDNA exhibited decreased performance or failure in blood stabilization and decreased sensitivity in downstream reactions depending on the age of the tubes.

*The PAXgene Blood ccfDNA Tube (CE-IVD) is intended for in vitro diagnostic use in Europe.