b'ClonalityTRG Clonality Assay TestsClinical Information Test Name used to identify DNA sequences specific to clonal gene The human T-Cell Receptor Gamma (TRG) locus onSince leukemias and lymphomas originate from theTRG Clonality Assayrearrangements. Bioinformatics tools facilitate the chromosome 7 (7q14) includes 14 variable (V) genesmalignant transformation of individual lymphoid cells,characterization of sequences present at greater than(Group I, II, III, and IV), 5 joining (J) gene segments, and which means that all leukemias and lymphomas generally2.5% of the population. These sequences can be2 constant (C) genes spread over 200 kilobases. 1 share one or more cell-specific or clonal antigenAssay Type used to track specific clonal populations.Lymphoid cells are different from the other somatic cellsreceptor gene rearrangements. Clonality does not alwaysNext-Generation Sequencing (NGS)in the body, as during development the antigen receptorimply malignancy; all results must be interpreted in theIndications for Testingcontext of all of the other available diagnostic criteria.This test is performed by using the LymphoTrack or genes in lymphoid cells (including gene segments within dentify clonality in atypical lymphoproliferative Tests that detect TRG clonal rearrangements can be usedLymphoTrack Dx Assay from Invivoscribe. Ithe TRG locus), undergo somatic gene rearrangement. 2 to help identify T-cell and certain B-cell malignancies.disordersThese developmentally regulated, programmed geneSupport a differential diagnosis between reactiverearrangements generate V-J combinations that areMethod Description lesions and hematologic malignanciesunique for each cell. 3 For detection of the vast majority of TRG gene Assign presumptive lineage in mature monoclonalNote: During T-cell ontogeny, rearrangement of the TRG locus occurs before rearrangement of the alpha beta loci. rearrangements, a multiplex master mix targetinglymphoproliferative disordersTherefore, clonal rearrangements of TRG are often present, commonly detected, and can be tracked in T-cell malignanciesthe V and J regions are used for PCR amplification.Monitor and evaluate disease recurrenceinvolving alpha-beta T-cells. This makes TRG a powerful tool for both clonal and MRD analysis of T-cell and some B-cell tumors. Next-generation sequencing of the PCR products is Interpretation TurnaroundSpecimenShippingSpecimen Time Requirements Conditions StabilityAn interpretive report will be5 to 10 1-3 mL of peripheralAmbient or2-8 C up issued indicating whetherbusiness daysblood in Heparin, Cool; doto 7 days prior evidence of clonality wasEDTA or ACD not freezeto testing detected. The report further0.25-1 mL of bone(peripheral provides a summary of theblood or bone top 5 merged sequences,marrow in Heparin,marrow) including the % total reads, theEDTA or ACDrearrangement class and the 500 ng of previouslyAmbient or sequence. isolated DNAfrozen on dry ice (isolated References DNA)1.LC Lawnickie, et al. (2003). The distribution of gene segments in T-cell receptor gamma gene rearrangements demonstratesthe need for multiple primer sets. J Mol Diagn. 5:82-87.2. Tonegawa S (1983) Somatic Generation of Antibody Diversity. Nature 302:575-581.3.JE Miller et al., Molecular Genetic Pathology (2013, 2nd ed.) Springer Science & Business Media 302.2.7.13 and 30.2.7.18.32 LabPMM Services Catalog 2021|33'