*Purpose: The purpose of this study was to evaluate the role of cell-free DNA testing ( Allosure, CareDx, Brisbane , CA) during graft dysfunction in kidney transplant recipients who had received kidneys from donors with Sub-Optimal Donor Quality (SODQ).

*Methods: SODQ kidneys were defined as kidneys that had undergone a biopsy by the Organ Procurement Organization at the time of procurement. The most common indications for biopsy by the OPO were : Donor hx of HTN, DM and AKI. All SODQ Kidney’s that had subsequently undergone a for cause kidney biopsy, and Allosure testing (ASt) were included in the analysis. Data was collected regarding the final diagnosis of the for cause biopsy and the ASt results.

*Results: 60 patients were identified to have underwent an procurement biopsy, a for cause biopsy and an ASt. 20/60 had had AS testing performed within a month prior to the for cause biopsy and others either >4 prior or after and were not used in the analysis. 13/20 (65%) had rejections [7 BL/ Early TCR’s, two 1a’s, one 1b and 3 AMR’s ]. 3/20 pts had an AS of <0.15% ( 1BL/Early TCR, 1 diabetic changes and 1 with mild ATN), 5/20 had ASt >1% (2AMR’s, one 1b, one 1a, 1 BL). ASt identified 1a or greater rejections in 4/6 (67%) pts with a 1% cutoff. The mean ASt for BL/early TCR rejection was 0.42 % (0.15-1.5%). ASt for biopsies with Moderate IF without rejection trended higher 0.58 % (0.35-0.80).

*Conclusions: SODQ Kidneys’s are more prone to graft dysfunction necessitating evaluations and biopsies. Our results demonstrates the following regarding ASt in SODQ Kidney’s : Over 85% patients who underwent a for cause biopsy have ASt>0.15%. While ASt was able to identify higher grades of rejection, a threshold <1% is warranted to identify BL rejections. Levels of >0.50 % may suggest the presence of higher grades of tubular atrophy due to donor quality and should be confirmed by evaluating the results of procurement biopsy. In the absence of moderate IF in baseline biopsies, ASt levels of >0.15- 1% should raise concerns for borderline rejections and be followed with a biopsy or empiric but careful adjustment in immunosuppression.

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