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HelpTest Code TCGBM T-Cell Receptor Gene Rearrangement, PCR, Bone Marrow
Reporting Name
T Cell Receptor Gene Rearrange, BMUseful For
Determining whether a T-cell population is polyclonal or monoclonal
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Specimen Type
Bone MarrowShipping Instructions
Specimen must arrive within 7 days of collection.
Necessary Information
Include relevant clinical information and cytogenetics results, if available.
Specimen Required
Container/Tube:
Preferred: Lavender top (EDTA)
Acceptable: Yellow top (ACD)
Specimen Volume: 2 mL
Collection Instructions:
1. Invert several times to mix bone marrow.
2. Send bone marrow specimen in original tube. Do not aliquot.
Specimen Minimum Volume
1 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Bone Marrow | Ambient (preferred) | 7 days | |
| Refrigerated | 7 days |
Special Instructions
Reference Values
An interpretive report will be provided.
Positive, negative, or indeterminate for a clonal T-cell population
Day(s) Performed
Monday through Friday
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 US 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)
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| TCGBM | T Cell Receptor Gene Rearrange, BM | In Process |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 19957 | Final Diagnosis: | 22637-3 |
| 608952 | Signing Pathologist | 19139-5 |
Testing Algorithm
For information see:
-Bone Marrow Staging for Known or Suspected Malignant Lymphoma Algorithm
Clinical Information
The T-cell receptor (TCR) genes (alpha, beta, delta, and gamma) are comprised of numerous, discontinuous coding segments that somatically rearrange to produce heterodimeric T-cell surface 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, polymerase chain reaction) and used to determine if a population of T cells shows monoclonal or polyclonal features.
Interpretation
An interpretive report will be provided.
Results will be characterized as positive, negative, or indeterminate for a clonal T-cell population.
In the appropriate clinicopathologic setting, a monoclonal result is associated with a neoplastic proliferation of T cells (see Cautions).
Method Description
Genomic DNA is extracted from the bone marrow. T-cell receptor beta (TCRB) and T-cell receptor gamma (TCRG) loci (official designations TRB and TRG, respectfully) are amplified by polymerase chain reaction (PCR) using a multiplex primer method based on the BIOMED-2 strategy. Specific primers are labeled with fluorochrome dyes, permitting precise fragment sizing of PCR products by capillary gel electrophoresis using a genetic analyzer. Each amplified locus is assessed for gene rearrangement patterns and an overall interpretation of the assay is made with regards to the presence or absence of a monoclonal population.(Unpublished Mayo method)
Reject Due To
| Gross hemolysis | Reject |
| Moderately to severely clotted | Reject |
Method Name
Polymerase Chain Reaction (PCR)
Forms
1. Hematopathology Patient Information (T676)
2. If not ordering electronically, complete, print, and send a Hematopathology/Cytogenetics Test Request (T726) with the specimen.