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HelpTest ID TCGRV T-Cell Receptor Gene Rearrangement, PCR, Varies
Useful For
Determining whether a T-cell population is polyclonal or monoclonal
Special Instructions
Method Name
DNA Extracted for Analysis/Polymerase Chain Reaction (PCR)
(PCR is utilized pursuant to a license agreement with Roche Molecular Systems, Inc. and InVivoScribe Technologies)
Reporting Name
T Cell Receptor Gene Rearrange, VSpecimen Type
VariesForms:
1. Hematopathology Patient Information Sheet (Supply T676) in Special Instructions
2. If not ordering electronically, complete, print, and send a Hematopathology/Cytogenetics Test Request Form (T726) with the specimen
(http://www.mayomedicallaboratories.com/it-mmfiles/hematopathology-request-form.pdf)
Body fluid or spinal fluid specimens must arrive within 96 hours of collection.
Submit only 1 of the following specimens:
Specimen Type: Body fluid
Container/Tube: Sterile container
Specimen Volume: At least 5 mL
Collection Instructions:
1. If the volume is large, pellet cells prior to sending.
2. Send less volume at ambient temperature or as a frozen cell pellet.
Specimen Stability Information:
Body fluid: Ambient/Refrigerated/Frozen
Cell pellet: Frozen
Specimen Type: Paraffin-embedded bone marrow aspirate clot
Container/Tube: Paraffin block
Specimen Stability Information: Ambient/Refrigerated
Specimen Type: Frozen tissue
Container/Tube: Plastic container
Specimen Volume: 100 mg
Collection Instructions: Freeze tissue within 1 hour of collection.
Specimen Stability Information: Frozen
Specimen Type: Paraffin-embedded tissue
Container/Tube: Paraffin block
Specimen Stability Information: Ambient/Refrigerated/Frozen
Specimen Type: Spinal fluid
Container/Tube: Sterile vial
Specimen Volume: 5-10 mL
Specimen Stability Information: Ambient/Refrigerated
Specimen Type: Extracted DNA from blood or bone marrow
Container/Tube: 1.5- to 2-mL tube with indication of volume and concentration of DNA
Specimen Volume: Entire specimen
Collection Instructions: Label specimen as extracted DNA from blood or bone marrow
Specimen Stability Information: Refrigerated/Ambient
Specimen Minimum Volume
Body Fluid or Spinal Fluid: 1 mL/Tissue: 50 mg/Extracted DNA from Blood or Bone Marrow: 50 microliter at 20 ng/microliter
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Varies | Varies | |
Clinical Information
The T-cell receptor (TCR) genes (alpha, beta, delta, and gamma) are comprised of numerous, discontinuous coding segments that somatically rearranged to produce heterodimeric cell surface T-cell receptors, either alpha/beta (90%-95% of T cells) or gamma/delta (5%-10% of T cells). With rare exceptions (eg, some neoplastic B-lymphoid proliferations), other cell types retain the "germline" configuration of the TCR genes without rearrangement.
The marked diversity of somatic TCR-gene rearrangements is important for normal immune functions, but also serves as a valuable marker to distinguish abnormal T-cell proliferations from reactive processes. A monoclonal expansion of a T-cell population will result in the predominance of a single TCR-gene rearrangement pattern. In contrast, reactive T-cell expansions are polyclonal (or multiclonal), with no single clonotypic population predominating in the population of T cells. These distributive differences in both TCR sequence and genomic rearrangement fragment sizes can be detected by molecular techniques (ie, PCR) and used to determine if a population of T cells shows monoclonal or polyclonal features.
Reference Values
An interpretive report will be provided.
Positive, negative, or indeterminate for a clonal T-cell population
Cautions
To determine the significance of the result, it must always be interpreted in the context of other clinicopathologic information.
The interpretation of the presence or absence of a predominant T-cell receptor (TCR)-gene rearrangement profile is sometimes subjective.
The detection of a clonal TCR-gene rearrangement by this test is not necessarily synonymous with the presence of a T-cell neoplasm. False-positive results can occur because of the sensitivity of PCR technique and the problem of nonuniform (skewed) amplification of target T-cell gene rearrangements. The latter problem can occur when the total T-cell number in a sample is limited, or because of physiologic skewing of the T-cell repertoire as seen with aging, posttransplantation, or T-cell reactions in autoimmune or (nonlymphoid) malignancies. False-negative results can occur for many reasons, including tissue sampling, poor amplification, or failure to detect a small minority of T-cell gene segment rearrangements with the use of consensus PCR primers. In some cases, an indeterminate or equivocal result will occur because the pattern of gene rearrangements is abnormal (compared to typical polyclonal T-cell processes), but not definitive, for a monoclonal T-cell population. In these situations, distinction of a small monoclonal subpopulation from an over-represented, but reactive, population may not be possible.
Day(s) Performed
Monday through Friday
Report Available
7 daysPerforming Laboratory
Mayo Medical Laboratories in Rochester
Test Classification
This test was developed using an analyte specific reagent. Its performance characteristics were determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.CPT Code Information
81340-TCB (T cell antigen receptor, beta) (eg, leukemia and lymphoma), gene rearrangement analysis to detect abnormal clonal population(s); using amplification methodology (eg, PCR)
81342-TCG@ (T cell receptor, gamma) (eg, leukemia and lymphoma), gene rearrangement analysis, evaluation to detect abnormal clonal population(s)