This is a prospective, multi-center, observational study. Subjects will have OmniGraf™ (TruGraf® and TRAC™) testing at study enrollment and thereafter every 3 months. In addition subjects will have OmniGraf™ (TruGraf® and TRAC™) testing at any time there is a clinical suspicion of acute rejection. Data collection for the primary objective extends over a 2-year period.

Several studies have validated TruGraf® in stable renal transplant patients to rule out subclinical acute rejection. These studies generally evaluated the diagnostic value of TruGraf® at single timepoints. Thus the value of serial monitoring and changes over time has not been previously investigated. In addition, no study has assessed TruGraf® and TRAC™in a serial and longitudinal fashion.

Therefore the aim of this study is to evaluate the impact of serial monitoring renal transplant patients with both TruGraf® and TRAC™ on long term outcomes.

Inclusion Criteria:

• Written informed consent and HIPAA authorization;
• At least 18 years of age;
• Recipient of a primary or subsequent deceased-donor or living-donor kidney transplant;
• At least 3-months post-transplant;
• Stable serum creatinine (per Principal Investigator);
• Treated with any immunosuppressive regimen, and;
• Selected by provider to undergo OmniGraf™ (TruGraf® and TRAC™) testing as part of post-transplant care; and

Exclusion Criteria:

• Recipient of a combined organ transplant with an extra-renal organ and/or islet cell transplant;
• Recipient of a previous non-renal solid organ and/or islet cell transplant;
• Known to be pregnant;
• Known to be infected with HIV;
• Known to have Active BK nephropathy;
• Known to have nephrotic proteinuria (Per Principal Investigator);
• Participation in other biomarker studies testing clinical utility.

This study is an observational study in adult (age ≥ 18 years), kidney transplant patients who are at least one year from the time of transplant. Approximately 2000 subjects will be enrolled.