Author: Alexandra Sommer, Senior Product Manager, Clinical Diagnostics at Tecan
Blood tests are among the most commonly performed procedures for evaluating an individual’s overall health, providing a wealth of valuable information through a relatively straightforward and painless process. The extensive data contained within blood is increasingly being explored for diagnosing or monitoring of various health issues, including brain injuries, infections and even cancers.1-3 Traditionally, the separation of centrifuged blood into its primary components has been a slow and labor-intensive manual process that lacked standardization, which has placed laboratories under growing pressure to maintain accuracy in response to rising demand. This article highlights the benefits of using automation to precisely identify liquid-liquid interfaces, enabling the efficient separation of blood at a higher throughput compared to manual techniques.
The essential elements found in blood
The process of separating blood into its three primary components – plasma, buffy coat and erythrocytes – is a crucial stage in numerous research and clinical protocols, serving as the fundamental basis for a multitude of downstream applications. While all three components are valued by laboratories worldwide, the plasma and buffy coat layers are at the core of cutting-edge research for various clinical indications.
Plasma is central to many innovative assays – such as non-invasive prenatal testing and transplantation monitoring – and has the potential to revolutionize oncology. While conventional tissue biopsies remain the established standard for diagnosing many malignancies, they come with several limitations, including invasiveness and applicability challenges across various cancer types and patient populations. These hurdles are largely absent in the case of liquid biopsies, where the analysis of cell-free DNA (cfDNA) present in plasma offers a comprehensive perspective on tumor heterogeneity, with the potential to serve as a diagnostic and prognostic marker.6 This approach has the ability to make a difference in patient care, guiding clinical decisions by predicting response to therapies, monitoring markers for minimal residual disease in curative settings, and transforming companion diagnostics. Further validation of cfDNA in oncology applications is necessary for it to gain widespread acceptance in clinical practice.7 Advancements in automation and high throughput screening will be pivotal in enabling researchers to accurately and swiftly analyze cfDNA in extensive patient cohorts.
Despite comprising less than one percent of total blood volume, buffy coat holds significant importance in medical research and diagnostics, due to its high concentration of white blood cells and platelets. Many laboratories prefer to extract genomic DNA from the buffy coat – rather than whole blood – since researchers can isolate large quantities with just a small sample. This is critical for genome-wide association studies, and ensuring an ample supply of genetic material for biobanking and future genomics and proteomics research in various disease areas, including oncology, neurodegenerative diseases and metabolic disorders. Buffy coat is also a source of microRNAs, which have been studied for potential biomarkers for the prediction and diagnosis of different cancer types.
Challenges in blood sample separation
The widespread use of blood in research and diagnostics – in addition to surgeries and other medical treatments – is placing significant strain on biobanks working to meet the growing demand from laboratories. A big challenge for biobanks is that, unfortunately, traditional manual separation methods are slow and susceptible to human error, regardless of the technician’s level of expertise. For instance, the buffy coat forms an extremely thin layer between the plasma and erythrocytes, meaning that its isolation – typically carried out manually with a Pasteur pipette – is hard to standardize. This leads to varying recovery rates and an inconsistent number of red blood cells and plasma transferred together with the buffy coat. Even when automation is accessible, the detection of liquid-liquid interfaces after centrifugation can be problematic, as barcodes and labels may interfere with optical sensors. This, in turn, slows down processing times when labels need to be removed, as well as potentially leading to a loss of the chain of custody.
Streamlined phase separation
The complexities associated with whole-blood separation prompted Tecan to develop an innovative approach to liquid separation, which not only saves time but also enhances accuracy in laboratory workflows. The Phase Separator™ represents a significant leap forward in liquid-liquid phase separation technology, delivering precision and speed to streamline workflows, and enhanced efficiency in both research and clinical laboratories. This innovation is based on a unique pressure-based technology integrated into the Air Flexible Channel Arm™ (Air FCA) of the company’s flagship Fluent® Automation Workstation. This intelligent approach effectively addresses the crucial challenge of detecting liquid-liquid interfaces and separating adjacent phases with minimal contamination risks, making it exceptionally well suited for extracting plasma or buffy coat layers from centrifuged whole blood samples.
Tecan’s Phase Separator can achieve remarkable speeds when operating in either tubes or plates, thanks to its combined phase detection and pipetting action. Processing speed is further improved as all eight channels on the Air FCA work in parallel, enabling the aspiration of plasma from 24 tubes of centrifuged blood in under 10 minutes*, and it is twice as fast on dual-arm systems. These advantages come without the need for additional bench space or equipment maintenance. Moreover, the technology precisely detects liquid levels inside the tube or plate, avoiding any interference from barcodes or other markings.
Blood tests play a fundamental role in assessing overall health, providing valuable insights into various health issues. The separation of blood components has traditionally been a slow and manual process, posing challenges for laboratories amid increasing demand. Automation offers a solution to efficiently identify liquid-liquid interfaces, and Tecan’s Phase Separator – using a unique pressure-based phase boundary detection technology – offers precise and rapid liquid separation, reducing contamination risks while standardizing the process. This technology improves efficiency and accuracy in laboratory workflows, offering faster processing to speed up research and diagnostics.
For further information about Tecan’s Phase Separator, please visit www.tecan.com/phase-separator.
*Timing is volume dependent. Time given for separation volumes of 5 ml.
The Fluent Phase Separator is an open liquid handling platform. No performance claims are made by Tecan. Performance validation is required by the customer.
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- Abeje G, et al. Comparison of capillary, venous and buffy coat blood samples in detecting Plasmodium species among malaria suspected patients attending at Hamusite health center. A cross-sectional study. BMC Infect Dis. 2021;21(1). doi:10.1186/S12879-021-06290-6
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