Validation of Donor-Derived Cell-Free DNA (Dd-cfDNA) for Kidney Transplant Monitoring

Inclusion Criteria: 1. Subject is 18 years of age or older 2. At least 12 calendar days have elapsed since the subject received a kidney transplant. 3. Subject has provided legally effective informed consent 4. Subject agrees to comply with all study procedures Exclusion Criteria: 1. Kidney donor is an identical twin of the subject. 2. The subject has another previously transplanted organ in situ. 3. Subject has received a hematopoietic stem cell transplant. 4. Subject has received a bone marrow graft. 5. Subject has self-reported as pregnant. 6. In the opinion of the investigator, the subject's participation in the study would pose a risk to data integrity or to the subject's safety and welfare. Sample Inclusion Criteria: 1\. A graft biopsy is obtained within ±1 week of blood draw. * If blood draw is obtained after biopsy, blood draw should be taken at least 2 days after an uncomplicated biopsy procedure. Sample Exclusion Criteria: 1. Sample collected from someone that had an invasive graft biopsy ≤ 48 hours prior to blood draw. 2. Sample collected from subject that received immunosuppressive treatment for biopsy-proven acute rejection ≤ 30 days prior to blood draw 3. Sample collected from subject that received a blood transfusion ≤ 30 days prior to blood draw. 4. Sample collected from a subject that provided another sample for the study within the past 7 days.