The concentrations per milliliter of Y-chromosome–positive donor cells derived from QAS PCR results of samples collected from the 10 female trauma patients. All frozen whole-blood samples were subjected to the enrichment of CD4⁺, CD8⁺, CD15⁺, and CD19⁺ leukocyte subpopulations, followed by amplification, hybridization, and quantitation using human Y-chromosome–specific primers and probe. Y-axis represents the concentration of donor cells per milliliter of recipient’s blood.