Preanalytical robustness of blood collection tubes with RNA stabilizers

Efficient blood stabilization is essential to obtaining reliable and comparable RNA analysis data in preclinical operations. PAXgene (Qiagen, Becton Dickinson) and Tempus (Applied Biosystems, Life Technologies) blood collection tubes with RNA stabilizers both avoid preanalytical degradation of mRNA by endogenous nucleases and modifications in specific mRNA concentrations by unintentional up- or down-regulation of gene expression. Sixteen different preanalytical conditions were tested in PAXgene and Tempus blood samples from seven donors: different mixing after collection, different fill volumes and different 24-h transport temperature conditions after collection. RNA was extracted by column-based methods. The quality of the extracted RNA was assessed by spectrophotometric quantification, A260/A280 purity ratio, RNA Integrity Number (Agilent Bioanalyzer), miRNA quantative real time polymerase chain reaction (qRT-PCR) on two target miRNAs (RNU-24 and miR-16), mRNA quality index by qRT-PCR on the 3′ and 5′ region of the GAPDH gene, and the PBMC preanalytical score, based on the relative expression levels of the IL8 and EDEM3 coding genes. When PAXgene RNA and Tempus blood collection tubes were used following the manufacturers' instructions, there was no statistically or technically significant difference in the output RNA quality attributes. However, the integrity of the RNA extracted from Tempus collection tubes was more sensitive to fill volumes and effective inversion, than to storage temperature, while the integrity of RNA extracted from PAXgene collection tubes was more sensitive to effective inversion and storage temperature than to fill volumes. Blood collection tubes with different RNA stabilizers present different robustness to common preanalytical variations.