Interpretation Turn-around Time Specimen Requirements Shipping Conditions Storage Conditions  An interpretive report will be issued indicating whether evidence of clonality was detected. The report further provides a summary of the top 5 merged sequences, including the % total reads, the rearrangement class and the sequence. 5 to 10 business days •  3 mL of peripheral blood in Heparin, EDTA or ACD •  1 mL of bone marrow in Heparin, EDTA or ACD •  500 ng of previously isolated DNA • FFPE tissue samples Ambient or Cool; Do not freeze • Room Temp up to 72 hours •  2-8 °C up to 7 days Test Name TRB clonality assay Assay Type Next-Generation Sequencing (NGS) This test is performed by using the LymphoTrack® Assay from Invivoscribe. Method Description For detection of the vast majority of TRB gene rearrangements, a multiplex master mix targeting the Vß, Jß and Dß regions is used for PCR amplification. Next-generation sequencing of the PCR products is used to identify DNA sequences specific to clonal gene rearrangements. Bioinformatics tools facilitate the characterization of sequences present at greater than 2.5% or 5% of the population. These sequences can be used to track specific clonal populations. Indications for Testing •  Identify clonality in atypical lymphoproliferative disorders •  Support a differential diagnosis between reactive lesions and hematologic malignancies •  Assign presumptive lineage in mature monoclonal lymphoproliferative disorders • Monitor and evaluate disease recurrence Clonaltiy Tests LabPMM Services Catalog 2019 | 37 Clinical Information The human T-cell receptor beta (TRB) gene locus on chromosome 7 (7q34) includes 64-67 variable (Vß) gene segments (belonging to 30 subgroups), 2 diversity (Dß) gene segments, and 13 joining (Jß) gene segments, spread over 685 kilobases, making this locus far more complex than others. Nevertheless, accurate molecular analysis of the TRB genes is an important tool for the assessment of clonality in suspected T-cell and some B-cell proliferations, as TRB gene rearrangements occur not only in almost all mature T-cell malignancies, but also in about one-third of precursor B-acute lymphoblastic leukemias (B-ALL)1 . Lymphoid cells are different from the other somatic cells in the body, as during development the antigen receptor genes in lymphoid cells (including gene segments within the TRB locus), undergo somatic gene rearrangement2 . These developmentally regulated, programmed gene rearrangements generate combinations that are unique for each cell1 . Since leukemias and lymphomas originate from the malignant transformation of individual lymphoid cells, all leukemias and lymphomas generally share one or more cell-specific or “clonal” antigen receptor gene rearrangements. Clonality does not always imply malignancy; all results must be interpreted in the context of all of the other available diagnostic criteria. Tests that detect TRB clonal rearrangements can be used to help identify T-cell and certain B-cell malignancies. TRB Clonality Assay References 1. JE Miller et al., Molecular Genetic Pathology (2013, 2nd ed.) Springer Science & Business Media 302.2.7.13 and 30.2.7.18. 2. Tonegawa S (1983) Somatic Generation of Antibody Diversity. Nature 302:575-581 36