“…Eleven studies were from USA ( 21 , 23 – 28 , 31 – 36 ), 1 study from France ( 20 ), 1 study from Italy ( 22 ), and 1 study from Japan ( 29 ), and two studies from China ( 19 , 30 ). In total, eleven studies measured dd-cfDNA levels in graft rejection ( 19 , 21 , 22 , 25 , 26 , 28 – 30 , 32 , 34 ), 6 studies measured dd-cfDNA levels in ACR ( 23 – 25 , 27 , 31 , 33 ), and 7 studies measured dd-cfDNA levels in AMR ( 21 , 23 – 25 , 31 , 33 , 34 ), respectively. Eleven studies evaluated the diagnostic accuracy of circulating dd-cfDNA in graft rejection ( 19 , 21 – 25 , 27 , 28 , 30 , 33 ), providing AUROC, sensitivity and specificity.…”