Transplantation often represents the only curative option for patients with serious health conditions such as end-stage organ failure or certain high-risk hematologic malignancies. Due to the prolonged immunosuppressive status of transplant patients, infections represent a significant cause of morbidity and mortality in this patient cohort. Therefore, clinical laboratories and the testing options they provide are essential for improving patient outcomes by facilitating the screening, diagnosis, and treatment response monitoring of infected transplant patients.