Non Invasive Blood Test To Diagnose Acute Rejection After Kidney Transplantation

Inclusion Criteria 1. Adult recipients (Age \> 18 years ) 2. Both genders and all racial and ethnic groups 3. Kidney transplant alone 4. Both living and deceased donor transplants 5. Primary and re-transplants. A total of 30 re-transplant recipients across all study sites will be eligible for enrollment. CareDx will notify all centers when this subset of enrollment has been met. Thereafter, all enrolled patients should be primary transplant recipients. 6. Ability to come for follow-up and undergo biopsy (Performed in accordance to SOC) 7. Ability to give written informed consent prior to study enrollment Patients can be enrolled at any time; before or after transplantation and/or at time of outpatient or inpatient visits for workup of medical problems; e.g. at the time of a renal biopsy (regardless of elapsed time since post transplant) as specified in this study protocol. Exclusion Criteria 1. Pediatric recipients (Age \< 18 years) 2. Pregnant women 3. Patients undergoing multi-organ transplants (e.g. kidney with pancreas or liver) 4. Patients receiving donor organ from an identical twin