Circulating cell-free DNA
Liquid biopsy

Circulating cell-free DNA

Get insights out of cfDNA

Cell-free DNA (cfDNA) is DNA found in biofluids free of its cellular origins. It carries real-time information that can be used to detect and monitor biomarkers of cancer and other diseases in a simple blood test. Understanding what is cfDNA is a first step in devising effective detection strategies.

cfDNA is often found in low concentrations with rare mutations and in a fragmented condition, and you need sensitive and reliable tools that give you confidence in the signal you detect. Whether you work in biomarker discovery, transplant or NIPT research, our products for cfDNA isolation and analysis give you the reliable results you need.

Precious samples, elusive cfDNA

Found in low concentrations, cfDNA contains only 1-2% circulating tumor DNA (ctDNA) in non-advanced, non-metastatic cancers. Isolation of cfDNA from low concentrations with high background noise requires handling of large starting volumes. High yields and purity are required for sensitive and reliable detection and analysis.

Sensitive detection and absolute quantification

Steps that increase standardization of the cfDNA analysis workflow include blood preservation and automated cfDNA isolation to ensure optimal purity and yield. Powerful discoveries are made possible by reliable detection of variants at a low variant allele frequency from cfDNA with an optimized bioinformatics pipeline and reduced enzymatic error rates. Biomarker validation and absolute quantification of cfDNA biomarkers in ultralow concentrations can be achieved by dPCR in reproducible results within 2 hours.

cfDNA analysis in detail

Comprehensive workflow solutions starting with blood collection and stabilization along the molecular analysis workflow from dedicated cfDNA preparation to integrated data analysis solutions for various applications by next-generation sequencing or digital PCR, scalable to your sample volume, throughput or outsourcing needs.

Products along the workflow

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  • Extend your in-house resources quickly and conveniently
  • Ensure your data is high quality using our expertise
  • Get support with just the time-consuming parts of your project or with your entire Sample to Insight journey
  • Benefit from expert consultation and make the best decisions to achieve your goals
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A range of different manual or automated cfDNA isolation systems are available to suit different starting volume, processing time and throughput needs. To help you choose the best combination of products to isolate cfDNA for your applications, see the graphics, or download the brochure that also includes information on cfDNA analysis by dPCR and next-generation sequencing and data interpretation systems.

Select products for research applications

Select products for diagnostic applications

cfDNA isolation from large starting volumes

The concentration of cfDNA in biological fluids such as plasma or urine is usually low and varies considerably between individuals, usually from 1–50 ng/ml. Typically, input volumes of 4 ml are used, which corresponds to the total plasma volume from one blood collection tube. Depending on the target DNA, the application, and the sensitivity of the downstream assay, the sample input volume needed can vary from 1 to 10 ml. We provide a range of cfDNA purification kits that offer fast workflows and unmatched cfDNA concentrations from varying sample inputs for high sensitivity in downstream NGS and PCR analyses.

Imagine analyzing a cfDNA eluate containing a very rare event. You might want to get the maximum possible input into the cell-free DNA analysis workflow. Combine up to 8 ml plasma sample processing on EZ2 Connect with high-volume eluate loading on QIAcuity.

Have you considered the power of two?

EZ2 Connect and QIAcuity for cfDNA analysis

If you isolate cfDNA from a larger volume of serum or plasma and then use large-volume eluate loading with a highly sensitive detection method like digital PCR, you can load more and see more. Processing larger volumes gets more template cfDNA and dPCR will detect more mutations. You can achieve this goal by combining EZ2 Connect for easy sample processing with the QIAcuity dPCR system.

You can now combine a fully automated and convenient high-volume sample processing on the EZ2 Connect with fast and sensitive ultra-low mutation detection using digital PCR on the QIAcuity.

Download The Power of Two

See for yourself
The best way to see the power of two is to try it out yourself. Complete the form to request a demo in your lab.

Learn from the cfDNA experts

Watch our webinars to gain insights from cancer researchers and cfDNA analysis technology experts. Here we’ve collected together our most popular cfDNA-related talks and Q&A sessions.
  • Cell-free DNA analysis – status and outlook
    Ellen Heitzer presents several studies evaluating various workflows for cfDNA analysis. Issues hampering the clinical implementation of cfDNA analysis and possible ways forward are discussed.
  • Liquid profiling for taking care of patients – still a controversial issue?
    Dr. Michael Fleischhacker, DRK Kliniken Berlin | Mitte, Germany

    The most recent version of the "S3 Guidelines for Prevention, Diagnostics, Therapy and Follow-up care of lung cancer patients" (Feb 2018) asks for applying a liquid biopsy in different clinical settings. This fact clearly demonstrates the usefulness of this approach. On the other hand, we should be aware that our knowledge of extracellular nucleic acid basics is still limited. These are the two poles between which my lecture moves.

  • Standardized preanalytics: The key for reliable diagnostics, research and biobanking

    Dr. Uwe Oelmueller, Vice President Head of MDx Development EU, Sample Technologies, QIAGEN

    Compromised patients’ samples often make in vitro diagnostic and research test results unreliable or even impossible. To tackle this challenge, the EU Horizon2020 SPIDA4P consortium is developing and implementing 22 pan-European pre-analytical CEN/Technical specifications and ISO/ international standards for workflows applied to personalized medicine. These specifications, workflows and standards will apply to medical laboratories and their customers, diagnostics developers and manufacturers, regulatory authorities, biobanks and institutions performing biomedical research. Corresponding External Quality Assurance (EQA) schemes have also been developed, aiming to survey the resulting quality of samples. SPIDIA4P is ensuring broad stakeholder involvement, training, education and counseling to support standards implementation.

  • Standardization in cell-free DNA sample processing
    A deep dive into cell-free DNA: learn about a true walkaway solution for automated isolation from up to 8 ml. And hear from Constanze Kindler, Ph.D. about challenges and new solutions for analyzing cfDNA from up to eight milliliters of blood.
  • cfDNA collection/stabilization and sample preparation
    Martin Schlumpberger and our panel of experts answer your questions on how to collect, stabilize and process your samples when working with cfDNA. Get answers, tips and tricks to ensure a successful start to your analysis.
  • cfDNA Digital PCR
    Özlem Karalay and our dPCR experts dive deep into the exciting analysis opportunities offered by dPCR technologies. Check out how sensitive and accurate your cfDNA analysis can be.
  • cfDNA NGS (SNV, CNV, methyl markers) and data analysis
    Want to use the power of NGS to analyze your samples? Peter Hahn and our next-generation sequencing experts answer all your questions in this final panel discussion on cfDNA analysis.
  • Ellen Heizer
    Cell-free DNA analysis – status and outlook
  • Liquid profiling for taking care of patients – still a controversial issue?
  • Standardized preanalytics: The key for reliable diagnostics, research and biobanking
  • Standardization in cell-free DNA sample processing
    Standardization in cell-free DNA sample processing
  • cfDNA collection/stabilization and sample preparation
    cfDNA collection/stabilization and sample preparation
  • Oezlem Karalay
    cfDNA Digital PCR
  • Peter Hahn
    cfDNA NGS (SNV, CNV, methyl markers) and data analysis


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