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Abstract: PO2195

Diagnostic Performance of Donor-Derived Cell-Free DNA Assay (AlloSure®) in Kidney Transplant Recipients with Graft Dysfunction: A Single-Center Study

Session Information

Category: Transplantation

  • 1902 Transplantation: Clinical


  • Naseer, Muhammad Saad, Willis Knighton Medical Center, Shreveport, Louisiana, United States
  • Singh, Ayush, Willis Knighton Medical Center, Shreveport, Louisiana, United States
  • Singh, Neeraj, Willis Knighton Medical Center, Shreveport, Louisiana, United States

Circulating donor-derived cell-free DNA (dd-cf-DNA) is a non-invasive biomarker of kidney allograft injury with a high negative predictive value for ruling out active rejection in patients with evidence of graft dysfunction. At our center, we compared the AlloSure® test (CareDx®) for the dd-cfDNA assays using >1% as the cut-off value suggested by the DART study or an increase of >30% from the previous value against the gold standard biopsy results and calculated its performance metrics.


From Dec 2019 to Oct 2020, we found 16 patients who had their 21 AlloSure® assays drawn which were within 4 weeks of for-cause biopsy sampling. In assessing the cause of 21 biopsy samples, 20 had AKI, 5 had proteinuria, and 3 had clinical symptoms of volume overload.


AlloSure® and biopsy results were concordant in 14/21 (66.7%) samples [Table 1]. Of the 21 for-cause biopsies, 8 biopsies were positive for rejection (2 borderline, 1 TCMR, 3 AMR, 1 mixed AMR/TCMR, 1 chronic). AlloSure® was positive in 2 of these rejections (1 TCMR, 1 mixed AMR/TCMR). However, it was false-negative in the other 6 rejections (2 borderline, 3 AMR, 1 chronic). Out of the 13 negative biopsy results, AlloSure® was negative in 12 samples and false-positive in one sample. The performance metrics in this patient population were: sensitivity 25%, specificity 92.3%, positive and negative predictive values of 66.7%, and accuracy of 66.7%.


Although we had a sample size, it can be concluded from this study that AlloSure® has a high specificity to diagnose active graft rejection in kidney transplant recipients.

Table 1: 2 x 2 Table