Test Details: The intended use of this assay is for routine post-transplant documentation of the donor/recipient origin of white blood cells in peripheral blood and/or bone marrow. Additional clinical indications include: • Prognostic testing for risks of graft rejection and recurrence of disease. • Document presence of donor cells in post-transplant patient with residual disease or prior to donor lymphocyte infusion (DLI). • Evaluate donor/recipient cells in patients with inadequate marrow function. • Determine if malignancy is a recurrence or new occurrence from donor cells. • Differentiate donor cell population in recipients who have received multiple transplants.