Blood sample collection and rapid separation—critical preanalytical steps in clinical chemistry—can be challenging in decentralized collection settings. To address this gap, the Torq™ zero delay centrifuge system includes a lightweight, hand-portable centrifuge (ZDrive™) and a disc-shaped blood collection device (ZDisc™) enabling immediate sample centrifugation at the point of collection. Here, we report results from clinical validation studies comparing performance of the Torq System with a conventional plasma separation tube (PST). Blood specimens from 134 subjects were collected and processed across three independent sites to compare ZDisc and PST performance in the assessment of 14 analytes (K, Na, Cl, Ca, BUN, creatinine, AST, ALT, ALP, total bilirubin, albumin, total protein, cholesterol, and triglycerides). A 31-subject precision study was performed to evaluate reproducibility of plasma test results from ZDiscs, and plasma quality was assessed by measuring hemolysis and blood cells from 10 subject specimens. The ZDisc successfully collected and processed samples from 134 subjects. ZDisc results agreed with reference PSTs for all 14 analytes with mean % biases well below clinically significant levels. Results were reproducible across different operators and ZDisc production lots, and plasma blood cell counts and hemolysis levels fell well below clinical acceptance thresholds. ZDiscs produce plasma samples equivalent to reference PSTs. Results support the suitability of the Torq System for remotely collecting and processing blood samples in decentralized settings.

Pseudomonas aeruginosa biofilms are implicated in chronic infections. A key element of P. aeruginosapathogenicity is the formation of a biofilm, a community of bacteria encased in an exopolymeric substance (EPS) that shields the bacteria from the host immune response and antibiotic treatment. A crucial step in biofilm production is a switch in motility from freely swimming, planktonic bacteria to twitching movement and then to attached and sedentary bacteria that develop into a mature pillar-shaped biofilm. A mucoid biofilm produces an excess of alginate and is clinically the most pathogenic and the most resistant to antibiotics. Biofilms from patients exhibit a wide variety of structure, motility, and levels of attachment. In vitrobiofilms do not exhibit such a wide variety of structure and physiology. The difference between in vivo and in vitro biofilms has made the translation of in vitro studies into in vivo treatments difficult. Under different growth conditions in our lab, the P. aeruginosa strain PAO1 demonstrates two phenotypes: a non-mucoid and a mucoid-like phenotype. Confocal laser scanning microscopy (CLSM) indicates the mucoid-like phenotype is intermediate in height to the non-mucoid phenotype and biofilms formed in a once-flow-through chamber. Both mucoid-like and non-mucoid phenotypes exhibit a significant increase in twitching between 24 and 72 hours of development. The mucoid-like phenotype had greater attachment at 72 hours compared to non-mucoid phenotype. Therefore, the two phenotypes observed in our lab may represent the effect of environment to stimulate development of two types of biofilms by PAO1.

Quantifying circulating tumor DNA (ctDNA) markers for liquid biopsy testing often requires shipping blood samples to centralized laboratories. Mechanical damage to blood cells can occur during transport, especially if samples endure extensive vibration and temperature excursions. Such mechanical damage may result in Red Blood Cell (RBC) disruption known as in vitro hemolysis, as well as White Blood Cell (WBC) lysis leading to the release of nuclear DNA and several types of nucleases into the plasma. Nuclear DNA and nuclease contamination are the primary interfering factors impeding ctDNA recovery. Several commercial products are developed to address this issue by chemically stabilizing the cells in the tube during transport (e.g., the Streck cell-free DNA BCT™). Nevertheless, such products do not entirely resolve the problem, and cell lysis during shipping remains a complication. The Torq™ zero delay centrifuge system offers a novel solution by immediately centrifuging and separating plasma from the cell component at the point of collection, after the blood draw and prior to shipping, preventing ctDNA dilution from whole blood interferents. Here we compare hemolysis levels in blood samples collected and prepared by the Torq system and Streck BCTs following simulated shipping conditions including time, vibration, and temperature excursions. Blood samples from healthy individuals were collected into Torq ZDiscs™ and Streck BCTs. The plasma was immediately separated within the ZDiscs using the Torq ZDrive™ and transferred to microtubes. The specimens in Streck BCTs remained as whole blood, as per the manufacturer's instructions. Both sample types went through shipping simulation for 24 and 72 hours following ISTA 3A standards while experiencing temperature conditions of 4°C, 24°C, and 40°C. The blood within Streck BCTs was separated into plasma and cell components after reaching the designated time point, and all samples were inspected for hemolysis by quantifying hemoglobin content. Samples collected and processed with the Torq zero delay centrifuge system showed minimal hemolysis throughout the simulation and at all temperature conditions, whereas samples in the Streck BCTs exhibited significantly higher hemolysis, especially after 72 hours (p-value: 0.0001). Streck samples stored at 4°C and 40°C were notably susceptible to high hemolysis contamination. Compared to the Torq system, the Streck BCTs yielded significantly increased sample hemolysis following simulated shipping times and temperature excursions (both low and high), thereby increasing the likelihood of genomic contamination. The ZDiscs provide enhanced shipping resiliency and decreased nuclear DNA background, thus increasing the chance for rare mutation detection in liquid biopsy applications. Citation Format: Ali Rahimian, Kyungjin Hong, Clara Neal, Gabriella Iacovetti, Greg Sommer, Ulrich Schaff. TorqTM system improves liquid biopsy sample shipping stability [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 3103.

e14529 Background: Sample quality is a critical consideration for high fidelity cell-free DNA (cfDNA) testing. Oncological cfDNA tests used for liquid biopsy typically employ specialty blood collection tubes containing chemical preservatives to minimize degradation of samples prior to lab testing. Here we describe a newly developed device, Zero Delay Plasma– a portable centrifuge and disc system designed to immediately isolate cell-free plasma at the point of blood draw – and evaluate its performance against the Streck cfDNA collection tube. Methods: Whole blood was collected, processed, and stored at room temperature for up to 7 days with both the Zero Delay Plasma system and the Streck cfDNA blood collection tube. Sample hemolysis was measured via cell-free hemoglobin. Genomic contamination and cfDNA signal-to-noise were evaluated by qPCR and electrophoresis, comparing signal from target 150-200bp cfDNA to contaminating longer length genomic sequences in the sample. 2 sets of hemolysis experiments, 2 sets of electrophoresis experiments and 4 sets of qPCR experiments were conducted. Results: Plasma processed with the Zero Delay Plasma system yielded ~4X lower hemolysis levels, ~10X lower genomic contamination, and ~20X higher cfDNA signal-to-noise compared to the Streck cfDNA collection tube after 7 days of storage at room temperature. Conclusions: The Zero Delay Plasma system minimizes sample degradation and analytical background signal for cfDNA testing by immediately removing cells and other contaminants at the point of blood collection. Clinical evaluations are in process.