The purpose of this research is to collect blood samples and data from kidney transplant patients. The samples and data will be used for research and development of non-invasive test to detect donor-derived cell-free DNA (dd-cfDNA) in kidney transplant patients to evaluate the status of the transplanted organ.

This is a prospective, multicenter sample collection study within a kidney transplant population.

Whole blood samples and clinical data will be obtained from each participant at the time of indication biopsy (prior to the biopsy procedure).

De-identified leftover retrospective gDNA screening samples from the paired donor(s) will also be obtained.

Inclusion Criteria:

1. Willing and able to provide written informed consent
2. Is 18 years of age or older at enrollment
3. Had a kidney transplant prior to enrollment
4. Is having an indication (for cause) biopsy as determined by clinician
5. retrospective leftover samples are available from the kidney donor(s).

Exclusion Criteria:

1. Is pregnant
2. Had a blood transfusion within the past 4 weeks
3. Had a transplant from an identical (monozygotic) twin
4. Had transplants of multiple organs from the same donor (eg, kidney and liver transplant).
5. Had transplants of more than 2 organs from different donors (eg, recipient of a third kidney transplant)
6. Had a transplant of hematopoietic stem cells (eg, bone marrow) or tissue (eg, heart valve)

Kidney Transplant Recipients

We do not plan to share individual participant data with other researchers. Any shared data will be de-identified data at the cohort level in aggregate.