Abstract: This invention provides a system and method for an assay used in determining appropriate immunosuppressant levels relative to organ transplant in which PBMC is separated from whole blood by Ficoll®. An aliquot of PBMC is used for phenotyping of cells. CD4, CD8, memory and naïve subsets, B-cells regulatory T-cells and other cell markers (e.g. CD31) are examined. After an aliquot of PBMC is taken, CD4 cells are isolated. DNA is isolated from the cells. CD4 cells can be used for TREC at the defined time points. The TREC assay can be performed via a validated protocol. TREC levels are then measured using a quantitative RT-PCR for single jointed TREC. Alternatively, or additionally, TREC-correlated cell markers (e.g. CD31) can be analyzed. Approximately 100,000 cells, or 2 micrograms, of DNA are desired for TREC analysis. Normal control cells are run in parallel. A kit, including instructions and various components can be provided.

Abstract: This invention provides a system and method for an assay used in determining appropriate immunosuppressant levels relative to organ transplant in which PBMC is separated from whole blood by Ficoll®. An aliquot of PBMC is used for phenotyping of cells. CD4, CD8, memory and naïve subsets, B-cells regulatory T-cells and other cell markers (e.g. CD31) are examined. After an aliquot of PBMC is taken, CD4 cells are isolated. DNA is isolated from the cells. CD4 cells can be used for TREC at the defined time points. The TREC assay can be performed via a validated protocol. TREC levels are then measured using a quantitative RT-PCR for single jointed TREC. Alternatively, or additionally, TREC-correlated cell markers (e.g. CD31) can be analyzed. Approximately 100,000 cells, or 2 micrograms, of DNA are desired for TREC analysis. Normal control cells are run in parallel. A kit for performing the assay, including instructions and various components can be provided for practitioners.