Objective:

To review the utility of donor-derived cell-free DNA (dd-cfDNA) testing in early detection of solid organ transplant injury, emphasizing its noninvasive nature.

Key Findings:

• dd-cfDNA levels are low under stable conditions but rise in cases of graft injury, indicating acute rejection.
• In kidney transplantation, dd-cfDNA can differentiate active rejection from stable graft function, potentially reducing unnecessary biopsies, as recommended by the American Society of Transplant Surgeons.
• In heart transplantation, dd-cfDNA is used in surveillance strategies to rule out significant rejection in stable patients.

Interpretation:

dd-cfDNA testing represents a significant advancement in transplant diagnostics, allowing for earlier and more personalized monitoring of graft health.

Limitations:

• Data on dd-cfDNA in liver and lung transplantation is less definitive, and the implications of standardization of assays are still in progress.

Conclusion:

As evidence accumulates, dd-cfDNA testing is likely to become a key component of transplant laboratory medicine, emphasizing the need for ongoing research.