Using Reverse Transcriptase Polymerase Chain Reaction (RT-PCR) and microfluidics on the Fluidigm Biomark HDTM system (Fluidigm, South San Francisco, CA) provides the potential for more rapid and quantitative analysis of gene expression, while requiring less RNA input and substantially reducing turnaround time. We performed analytical and clinical validation between the RT-PCR and microarray processes; not only did we find them to be analytically non-inferior, but we observed strong improvement in the clinical performance West-Thielke PM, et al. J Transplant Technol Res, Volume 12:3, 2022 Page 2 of 3 (in press). The Palmetto GBA Molecular Diagnostic Program (MolDX®) agreed and approved conversion of TruGraf methodology from microarray to PCR for CMS coverage. Further, we found that we could reliably provide sufficient sample for both TRAC Dd-cfDNA and TruGraf GEP using one single HemaSure-OMICS tube (Mawi, Hayward, CA) containing 6 mL of blood, a significant improvement from the ~15 mL of blood previously required to run both. The resulting combination biomarker panel is OmniGrafTM. Here we present the impact of the transition from TruGraf microarray to TruGraf PCR [5]. Using the same biopsy-paired samples as Park, we saw an improvement in the NPV from 88% to 94% when both assays were negative. Perhaps more importantly, we observed an increase in the PPV from 81% to 89% when both tests were positive (Figure 1A and 1B). False negative results were reduced from 31% to 17%, while true negative results improved from 74% to 81%. With OmniGraf, we observed 26.2% of results to be positive for one test and negative for the other: 11.7% showed elevated TRAC (+) and a TX TruGraf (-); 14.5% showed a TruGraf not-TX (+) and low TRAC score (-). Park and colleagues commented that TruGraf was significantly better at detecting subclinical TCMR and TRAC was significantly better at detecting subclinical ABMR; however, this methodological improvement in TruGraf technology increased its detection of all subtypes of rejection (Figure 1C and 1D). When considering results that do not agree, it is important to note that each test preferentially detects a different type of rejection (TruGraf ACR and TRAC AMR). In the field of transplant biomarkers where high NPV values have been the focus we present novel clinical validation data on the first commercial biomarker panel with a high PPV. With the data presented here, OmniGraf results provide a high probability of either immune quiescence or subclinical rejection to support clinical decision-making