To evaluate the association between time-updated CMV and BK viral loads measured monthly by T-ID and the risk of CMV disease and/or biopsy-proven BK virus-associated nephropathy (BKVAN) during the first 12 months following kidney transplantation, accounting for the net immune environment (TTV viral load) and allograft injury (donor-derived cell-free DNA, dd-cfDNA).

• To characterize time-updated viral detection patterns (e.g., transient vs sustained CMV or BK signals) identified by T-ID prior to development of CMV disease or BKVAN.
• To evaluate the clinical utility of T-ID monitoring, defined by the frequency and type of clinical management actions taken following test results.
• To estimate the diagnostic performance of T-ID for clinically meaningful viral infection compared with standard-of-care (PCR) testing and clinical adjudication.
• To quantify lead time between T-ID detection of viral cfDNA and standard-of-care confirmation or initiation of therapy.
• To assess the safety of biomarker-informed management, including both rejection following infection-directed management and infection following rejection-directed management.

Inclusion Criteria:

• Participants must meet all the following criteria:

  • Written informed consent and HIPAA authorization obtained prior to any study-related data collection.
  • Age ≥18 years at the time of enrollment.
  • Recipient of a kidney transplant, including:
  • Primary or repeat kidney transplantation
  • Living-donor or deceased-donor transplantation
  • At 1 month post-kidney transplant at the time of enrollment.
  • Receiving maintenance immunosuppressive therapy per institutional standard of care.
  • Selected by the treating provider to undergo TRAC testing as part of usual post-transplant clinical monitoring.

Exclusion Criteria:

• Recipient of a combined organ transplant involving a non-renal solid organ (e.g., kidney-liver, kidney-heart) and/or islet cell transplantation.

• History of prior non-renal solid organ transplantation or islet cell transplantation.

• Known pregnancy at the time of enrollment.

• Known active viral infection at enrollment with any of the following:

• Hepatitis B surface antigen (HBsAg)-positive

• Hepatitis B virus (HBV) nucleic acid testing (NAT)-positive

• Human immunodeficiency virus (HIV) infection or HIV NAT-positive

• *Known active BK virus-associated nephropathy (BKVAN) or CMV disease at the time of enrollment.

• Medical, psychiatric, or social condition that, in the opinion of the Investigator, would interfere with the participant's ability to provide informed consent or comply with study procedures.

• Concurrent participation in another investigational biomarker study designed to evaluate clinical utility of post-transplant molecular diagnostics.

  • Participants with asymptomatic or low-level viral replication detected during routine clinical monitoring are eligible, provided there is no evidence of established CMV disease or BK virus-associated nephropathy at enrollment.

All subjects who meet eligibility criteria will be enrolled. As this is a non-interventional study, the protocol does not mandate any specific diagnostic, therapeutic, or management interventions. Clinical management decisions, including adjustments to immunosuppression, antiviral therapy, diagnostic testing, and biopsy decisions, remain entirely at the discretion of the treating clinicians.

All data collected will be analyzed and submitted to Journals publications.