On Aug. 6, 2025, CareDx announced the publication of the Kidney Allograft Outcomes AlloSure Registry (KOAR) study in the American Journal of Transplantation. The landmark prospective study demonstrates the clinical utility of AlloSure® donor-derived cell-free DNA (dd-cfDNA) in improving rejection detection and guiding biopsy decisions in kidney transplant recipients.

The KOAR study enrolled 1,743 patients across 56 U.S. transplant centers to evaluate the clinical utility of a dd-cfDNA surveillance protocol based on the DART study, which prescribed seven tests in year one and four annually in years two and three. A total of 18,584 AlloSure tests were obtained from the overall cohort.

Key findings include:

• Elevated AlloSure was associated with a 6-fold increase in rejection yield in surveillance biopsies (39% vs. 7%, p<0.001) and a 4-fold increase in for-cause biopsies (47% vs. 12%, p<0.001).
• AlloSure elevations were detectable up to four months before ABMR and one month before TCMR, supporting its role in early detection and longitudinal monitoring.
• In post-biopsy monitoring, AlloSure levels declined significantly following treatment, while serum creatinine remained unchanged, reinforcing AlloSure’s role in assessing treatment response.

The study also demonstrated that dd-cfDNA levels correlate with rejection severity, with higher levels associated with ABMR and mixed rejection, and lower levels linked to borderline or TCMR 1A. This stratification capability positions AlloSure as a critical tool for tailoring immunosuppression and biopsy decisions based on individual patient risk.