Donor-Derived Cell-Free DNA (dd-cfDNA): An Emerging Biomarker of Allograft Health in Solid Organ Transplant Recipients

By applying the latest in genomic technology, clinicians may be able to use cfDNA as a biomarker in solid organ transplantation.

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AlloSure measures the percent of donor-derived cell-free DNA in the total cell-free DNA present in blood from a solid organ transplant recipient.

Cell-Free DNA (cfDNA)

While DNA is most commonly found within cells, there are trace amounts of DNA that can be found circulating in an individual’s bloodstream. This DNA is a consequence of release from cells and is commonly referred to as circulating or cell-free DNA (cfDNA). cfDNA as a biomarker has been used to detect pathologies in other areas of healthcare such as oncology and prenatal testing.

AlloSure: A Clinical-Grade dd-cfDNA

CareDx has developed AlloSure, a proprietary analytically validated test using Next-Generation Sequencing, to quantify the percent of dd-cfDNA present in the blood of solid transplant recipients.

AlloSure utilizes targeted amplification of single nucleotide polymorphism sites (SNPs) to identify non-recipient (donor) DNA in the blood of transplant patients. This involves the extraction of cfDNA from stabilized plasma, followed by amplification and sequencing of 266 regions of the human genome. Using novel computational analysis, the fraction of donor-specific DNA is calculated. A detailed description of this process is available1.

The approach by CareDx enables identification of allograft DNA without requiring independent genotyping of the donor and the recipient

AlloSure: An Analytically Validated Test

AlloSure was developed by CareDx with the goal of providing consistent, reproducible, high quality information using clinical-grade sequencing. This approach has been analytically validated using external reference standards, methods-based proficiency testing, and standardized cloud-based computational analysis2.

AlloSure Features

  • Analytically validated test offered by CareDx.
  • Highly sensitive, 0.19% to 16% reportable range.
  • Does not require genotyping of donor or recipient.
  • Samples collected in Streck’s Cell-Free DNA BCT® with no additional processing or preparation required before shipping.
  • Performed in CareDx’s purpose-built, CLIA-certified, CAP‑accredited NGS laboratory.
  • Offered as a laboratory developed test.
  • Results reported within 72 hours of sample receipt at CareDx.

AlloSure is now available for order from CareDx

AlloSure is a proprietary, analytically validated test using NGS to measure levels of dd-cfDNA present in the blood of a transplant recipient.

References

1 Woodward et al., Proficiency Testing for and Surveillance of Heart Transplant Health Using Donor-Derived Cell-Free DNA. J Mol Diag 17:859. 2015.
2 Amit et al. Using Cell Free DNA Reference Standards to Evaluate the Analytical Performance of Circulating Tumor DNA Testing and Solid Organ Transplant Health Surveillance. BioTechniques. 2015 Oct; 59 (4): 248–250.

AlloSure is not available for testing samples that originate in the State of New York.