Stabilization of nucleated blood cells by cell stabilizing reagent (BCT reagent) present in the Cell-Free DNA BCT blood collection device and consequent prevention of cell-free DNA contamination by cellular DNA during sample storage and shipping have previously been reported. This study was conducted to investigate the effect of this novel cell stabilizing reagent on DNA amplification by PCR as compared to traditional cell stabilizing reagents, formaldehyde and glutaraldehyde. A 787 bp long DNA fragment from human glyceraldehydes-3-phosphate dehydrogenase (GAPDH) gene was amplified by PCR and used as model system. DNA samples and blood samples were treated with BCT reagent, 0.1% formaldehyde or 0.1% glutaraldehyde at room temperature. DNA amplification was studied using conventional and real-time quantitative PCR. Results indicate that exposure of DNA to the BCT reagent for up to 14 days had no effect on DNA amplification by PCR as compared to the untreated control DNA. However, there was statistically significant decrease in DNA amplification in the DNA samples treated with formaldehyde and glutaraldehyde. We conclude that the BCT reagent used in Cell-Free DNA BCT blood collection device to prevent cell-free DNA contamination by cellular DNA had no effect on DNA amplification by PCR.

BackgroundMessenger RNA (mRNA) expression levels in blood cells are important in disease diagnosis, prognosis and biomarker discovery research. Accurate measurements of intracellular mRNA levels in blood cells depend upon several pre-analytical factors, including delays in RNA extraction from blood after phlebotomy. Dramatic changes in mRNA expression levels caused by delays in blood sample processing may render such samples unsuitable for gene expression analysis.ObjectivesThis study was conducted to evaluate a blood collection tube, cell-free RNA-BCT® (RNA-BCT), for its ability to stabilize mRNA expression level in blood cells post-phlebotomy using indicator mRNAs in reverse transcription quantitative real-time PCR (RT-qPCR) assays.MethodsBlood samples from presumed healthy donors were drawn into both RNA-BCT and K3EDTA tubes and maintained at room temperature (18–22 °C). The samples were processed to obtain white blood cells (WBCs) at days 0, 1, 2 and 3. Total cellular RNA was extracted from WBCs and mRNA concentrations were quantified by RT-qPCR for glyceraldehyde-3-phosphate dehydrogenase (GAPDH), c-fos, and p53 transcripts.ResultsWhile blood cells isolated from K3EDTA tubes showed significant changes in cellular mRNA concentrations for GAPDH, c-fos, and p53, these mRNAs concentrations were stable in blood drawn into RNA-BCT.ConclusionThe reagent in the RNA-BCT device stabilizes cellular mRNA concentrations for GAPDH, c-fos and p53 for at least three days at room temperature.

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