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Test Code TCGR T-Cell Receptor Gene Rearrangement, PCR, Blood

Reporting Name

T Cell Receptor Gene Rearrange, B

Useful For

Determining whether a T-cell population is polyclonal or monoclonal

Performing Laboratory

Mayo Medical Laboratories in Rochester

Specimen Type

Whole blood


Shipping Instructions


Specimen must arrive within 7 days (168 hours) of draw.



Necessary Information


Include relevant clinical information and cytogenetics results, if available.



Specimen Required


Container/Tube:

Preferred: EDTA (lavender top)

Acceptable: ACD (yellow top)

Specimen Volume: 4 mL

Collection Instructions:

1. Invert several times to mix blood.

2. Send specimen in original tube.


Specimen Minimum Volume

1 mL

Specimen Stability Information

Specimen Type Temperature Time
Whole blood Ambient (preferred) 7 days
  Refrigerated  7 days

Reference Values

An interpretive report will be provided.

Positive, negative, or indeterminate for a clonal T-cell population

Day(s) and Time(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 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)

LOINC Code Information

Test ID Test Order Name Order LOINC Value
TCGR T Cell Receptor Gene Rearrange, B In Process

 

Result ID Test Result Name Result LOINC Value
18210 Final Diagnosis: 34574-4

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 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.

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).

Clinical Reference

1. Liu H, Bench AJ, Bacon CM, et al: A practical strategy for the routine use of BIOMED-2 PCR assays for detection of B- and T-cell clonality in diagnostic haematopathology. Br J Haematol 2007;138(1):31-43

2. Van Krieken JH, Langerak AW, Macintyre EA, et al: Improved reliability of lymphoma diagnostics via PCR-based clonality testing: report of the BIOMED-2 Concerted Action BHM4-CT98-3936. Leukemia 2007;21(2):201-206

3. Bruggemann M, White H, Gaulard P, et al: Powerful strategy for polymerase chain reaction-based clonality assessment in T-cell malignancies Report of the BIOMED-2 Concerted Action BHM4 CT98-3936. Leukemia 2007;21(2):215-221

Analytic Time

5 days

Reject Due To

Hemolysis

Mild OK; Gross reject

Lipemia

NA

Icterus

NA

Other

Moderately to severely clotted

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)

Forms

1. Hematopathology Patient Information (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)