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Abstract: SA-PO383

Correlation Between Percentage Donor-Derived Cell-Free DNA (%dd-cfDNA) at Time of Allograft Biopsy and Rejection: Insights from the Multi-Center Pediatric Outcomes of Kidney Care in Renal Allografts (pOKRA) Study

Session Information

  • Pediatric Nephrology - III
    November 04, 2023 | Location: Exhibit Hall, Pennsylvania Convention Center
    Abstract Time: 10:00 AM - 12:00 PM

Category: Pediatric Nephrology

  • 1900 Pediatric Nephrology


  • Dandamudi, Raja, Washington University in St Louis, St Louis, Missouri, United States
  • Walther, Leslie, Washington University in St Louis, St Louis, Missouri, United States
  • Kelton, Megan, Seattle Children's Hospital, Seattle, Washington, United States
  • Kamel, Margret, Emory University, Atlanta, Georgia, United States
  • Smith, Jodi M., Seattle Children's Hospital, Seattle, Washington, United States
  • Dharnidharka, Vikas R., Washington University in St Louis, St Louis, Missouri, United States

The is prospective multi-center observational study to assess the accuracy of % dd-cfDNA as a biomarker for the detection of allograft rejection on simultaneous biopsy, in pediatric kidney transplant patients.


A total of 48 patients from 3 centers who underwent kidney biopsies within the first year post-transplantation were included in the study. We measured %dd-cfDNA levels using a targeted, multiplex PCR-based method analyzing single nucleotide polymorphisms. Patients were divided into two groups based on the presence or absence of allograft rejection, including subclinical rejection.


We studied 77 samples of plasma %dd-cfDNA levels drawn on the same morning before kidney biopsies from 48 unique patients. Of 77 biopsies, 70 (91%) were surveillance biopsies, whereas 7 (9%) were diagnostic. We had 13 biopsy specimens from 12 patients with biopsy-proven acute rejection and 64 biopsy specimens from 44 patients without biopsy-proven acute rejection.
At rejection, the %dd-cfDNA median (IQR) level was significantly higher at 1.2% (IQR, 0.5%-2.0%) than the quiescent group (median, 0.26%; IQR, 0.18%-0.49%). The area under the curve was 0.82 (95% confidence interval 0.70 to 0.93).
Using a 1% cutoff, %dd-cfDNA had a specificity of 86 % (95% CI, 75% to 92%) and a sensitivity of 62 % (95% CI, 36% to 82%) in identifying active rejection. At the lower cutoff of 0.5%, %dd-cfDNA had a lower 75% specificity (95% CI, 63% to 84%) but higher 77% sensitivity (95% CI, 50% to 92 %) to discriminate biopsy-proven acute rejection from no rejection.


Prospective multicenter dd-cfDNA% levels timed to biopsy show a high accuracy with biopsy-proven acute rejection in children.


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