*Purpose: _{With the introduction of Cell free DNA(cfDNA) technology in transplantation a few years ago, and a more recent addition of genomic testing with TruGraf -surveillance of the renal allograft is moving beyond the serum creatinine.} The purpose of our study were two fold- 1. To see if previously performed serial cfDNA levels could predict TruGraf results. 2. To see if collective interpretation of the two tests could help in predicting the overall trend in renal function.

*Methods: Kidney transplant recipients who had undergone serial cell-free DNA testing (Allosure) and at least one TruGraf test were enrolled in the study. An Allosure test had to be have been performed within 5 days of the TruGraf. The following were collected ; mean of serial Allosure levels tested prior to Trugraf (cfDbaseln), Allosure on the day of Trugraf testing (cfDTruG), cfDNA change (Chng) [(cFDbaseln)- (cfDTruG)], Trugraf results as NotTX and Tx and the overall trend of renal function(CrTrnd) based on serum creatinines was classified as ;stable(s) , worsening(w) or improving(i).

*Results: 10 patients met the inclusion criteria. TruGraft results; 10 Not-Tx and 6 TX. The mean number of cfDNA testing done prior to the TruGraf test was Not-Tx 4 (1-6) and 4.6 for the Tx (2-9). The mean cfDbaseln ; Not-Tx :0.54% ( 0.13%-1.5%) vs TX: 1.39%(0.37%-3%), the mean cfDTruG ; Not-Tx :0.68% (0.12% to 2.7%) vs Tx 1.25% (0.26%-4.8%) , mean Chng; Not-Tx : -0.142% (-2.12% to 0.68%) vs Tx 0.14%(-1.8% to 1.93%), CrTrnd ; Not-Tx: 1 s, 7 w, 2 i vs Tx: s 4, w 0 ,i 2.

*Conclusions: In our small observational study, it appears that serial cell-free DNA may not predict the outcome of TruGraf results, and that when used together provide complimentary insights into grafts at higher risk of deteriorating renal function. Our study suggests that cfDNA is likely most meaningful when interpreted in the context of change from a baseline. A rise of cfDNA from baseline accompanied with a Non-tx TruGraf result was associated with graft instability. Current ongoing prospective registry studies may confirm our observations. Whether the mechanistic differences in injury account for these observations and can be validated by molecular microscopy remains undetermined.

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