Biomarker surveillance after solid organ transplant is an advancing field with promise for further elucidation through high-throughput analyses and "omics" technologies. To date, Gene Expression Profiling (GEP; AlloMap ) is the only FDA-cleared genomic assay as surveillance for moderate-severe TCMR versus allograft quiescence after heart transplantation. Clinical validity and utility, however, have been recently established after kidney and heart transplantation, for analysis of donor-derived cell-free DNA in the assessment for potential "Allograft Tissue Injury" that may occur during diverse processes such as T-Lymphocyte mediated (TCMR) or Antibody-mediated (ABMR) allograft rejection or allograft-associated infection. These genomic analytes are currently being explored and