Ordering Recommendations

Indications for testing include:
  1. Identification of clonal T cell populations suggestive of T cell malignancies
  2. Monitoring and evaluation of disease recurrence

Performed

Monday - Friday

Methodology

Polymerase Chain Reaction / Fragment Analysis

Reported

Routine: 5 - 7 days

Synonyms

  • T Cell Receptor Gamma Gene Rearrangement
  • T-Cell Receptor Gamma Gene Rearrangement
  • T Cell Receptor Gene Rearrangement
  • T-Cell Receptor Gene Rearrangement
  • T-Cell Gene Rearrangement
  • T Cell Gene Rearrangement
  • TCR Gamma Gene Rearrangements
  • TCRG Gene
  • T Cell Clonality
  • T Cell Lymphoma
  • Lymphoproliferative Disorders
  • Clinical Genomics

Performing Lab

Clinical Genomics

Turnaround Time

7 days

Add-on Eligibility

Yes, within 7 days of collection
*If DNA has been extracted previously for other Clinical Genomics tests, this is stored for 6 weeks and may qualify for add-on

Specimen Type

Blood

Specimen Volume

5 mL (Minimum: 1 mL)

Collection Container

EDTA Whole Blood Tube (Lavender Top Vacutainer)

Unacceptable Conditions

  1. Severely clotted or grossly hemolyzed specimens
  2. Specimens that have been improperly collected, stored, or transported
  • Specimens collected in preservatives other than EDTA
    • ACD tubes are accepted, but EDTA is preferred
  • Serum or plasma
  • Specimens that have been frozen
  • Commingled specimens
  1. Specimens in tubes that have been damaged or broken during transport
  2. Specimens with insufficient volume for testing
  3. Unlabeled or mislabeled specimens

Storage/Transport Temperature

Transport Instructions      
Collection Location Transport Temperature Processing Required Timeframe
ED/Inpatient Room Temperature None Specimen must be received by the lab within 3 days of collection
Laboratory/Outpatient/Off-Site Room Temperature None Specimen must be received by the lab within 3 days of collection

Storage: Refrigerated

Stability (from collection to initiation)

Stability:
Prior to Extraction:
  • Room Temperature: 3 days
  • Refrigerated: 7 days
  • Frozen: Unacceptable
Extracted DNA:
  • Room Temperature: Unacceptable
  • Refrigerated: Unacceptable
  • Frozen: Indefinitely

Laboratory Storage: 
  • Original Specimen: Refrigerated
  • Extracted DNA: Frozen
Laboratory Retention: 
  • Original Specimen: 1 month
  • Extracted DNA: 6 weeks

Collection Instructions

Labeling Instructions:
When labeling blood tubes, leave a small window visible for the lab to assess the fill volume and sample integrity. Ensure that the barcode is in the correct orientation.


Collection Instructions:
Follow the correct order of draw when collecting with additional orders and tube types:
     

Reference Interval

Not Detected: Negative for clonal rearrangement of the T cell receptor gamma gene

Interpretive Data

Rearrangement of the T cell receptor gamma chain (TCRG) gene occurs during ontogeny in T lymphocytes. The structure of these rearranged genes can be examined as a means of detecting a clonal population of T cells, such as is present in lymphoma and other T cell malignancies. A polymerase chain reaction (PCR) assay, in which primers are designed to produce small amplicons from the junction points of the rearranged TCRG gene segments, can be used for this purpose.  When every cell in a population has rearranged their TCRG genes differently, the PCR assay will produce a large number of products, each with a slightly different size, indicating a polyclonal population.  If a large number of cells harbor the same rearrangement of TCRG gene segments, the PCR product produced from these cells will be in much greater concentration than those produced from a polyclonal cell population, thus resulting in a "predominant" PCR amplicon size.  This is taken as evidence of a monoclonal population. 

Methodology: Polymerase chain reaction and capillary get electrophoresis

Limitations: Positive results are highly suggestive of malignancy; however, a positive result should not be used as the sole criterion for diagnosis. Both positive and negative results should be interpreted in the context of all clinical and laboratory findings. Up to 20% of T cell neoplasms can yield a false-negative result in this assay. Thus, a negative result with this assay cannot be used to exclude a T cell neoplasm.

This test was developed and its performance characteristics determined by the UC San Diego Health System Clinical Genomics Laboratory. It has not been cleared or approved by the US Food and Drug Administration. FDA clearance or approval is not required for clinical use. The result of this test should be interpreted using all relevant clinical data and should not be used alone for clinical diagnosis or patient management decisions.
Ordering

Ordering Recommendations

Indications for testing include:
  1. Identification of clonal T cell populations suggestive of T cell malignancies
  2. Monitoring and evaluation of disease recurrence

Performed

Monday - Friday

Methodology

Polymerase Chain Reaction / Fragment Analysis

Reported

Routine: 5 - 7 days

Synonyms

  • T Cell Receptor Gamma Gene Rearrangement
  • T-Cell Receptor Gamma Gene Rearrangement
  • T Cell Receptor Gene Rearrangement
  • T-Cell Receptor Gene Rearrangement
  • T-Cell Gene Rearrangement
  • T Cell Gene Rearrangement
  • TCR Gamma Gene Rearrangements
  • TCRG Gene
  • T Cell Clonality
  • T Cell Lymphoma
  • Lymphoproliferative Disorders
  • Clinical Genomics

Performing Lab

Clinical Genomics

Turnaround Time

7 days

Add-on Eligibility

Yes, within 7 days of collection
*If DNA has been extracted previously for other Clinical Genomics tests, this is stored for 6 weeks and may qualify for add-on
Collection

Specimen Type

Blood

Specimen Volume

5 mL (Minimum: 1 mL)

Collection Container

EDTA Whole Blood Tube (Lavender Top Vacutainer)

Unacceptable Conditions

  1. Severely clotted or grossly hemolyzed specimens
  2. Specimens that have been improperly collected, stored, or transported
  • Specimens collected in preservatives other than EDTA
    • ACD tubes are accepted, but EDTA is preferred
  • Serum or plasma
  • Specimens that have been frozen
  • Commingled specimens
  1. Specimens in tubes that have been damaged or broken during transport
  2. Specimens with insufficient volume for testing
  3. Unlabeled or mislabeled specimens

Storage/Transport Temperature

Transport Instructions      
Collection Location Transport Temperature Processing Required Timeframe
ED/Inpatient Room Temperature None Specimen must be received by the lab within 3 days of collection
Laboratory/Outpatient/Off-Site Room Temperature None Specimen must be received by the lab within 3 days of collection

Storage: Refrigerated

Stability (from collection to initiation)

Stability:
Prior to Extraction:
  • Room Temperature: 3 days
  • Refrigerated: 7 days
  • Frozen: Unacceptable
Extracted DNA:
  • Room Temperature: Unacceptable
  • Refrigerated: Unacceptable
  • Frozen: Indefinitely

Laboratory Storage: 
  • Original Specimen: Refrigerated
  • Extracted DNA: Frozen
Laboratory Retention: 
  • Original Specimen: 1 month
  • Extracted DNA: 6 weeks

Collection Instructions

Labeling Instructions:
When labeling blood tubes, leave a small window visible for the lab to assess the fill volume and sample integrity. Ensure that the barcode is in the correct orientation.


Collection Instructions:
Follow the correct order of draw when collecting with additional orders and tube types:
     
Result Interpretation

Reference Interval

Not Detected: Negative for clonal rearrangement of the T cell receptor gamma gene

Interpretive Data

Rearrangement of the T cell receptor gamma chain (TCRG) gene occurs during ontogeny in T lymphocytes. The structure of these rearranged genes can be examined as a means of detecting a clonal population of T cells, such as is present in lymphoma and other T cell malignancies. A polymerase chain reaction (PCR) assay, in which primers are designed to produce small amplicons from the junction points of the rearranged TCRG gene segments, can be used for this purpose.  When every cell in a population has rearranged their TCRG genes differently, the PCR assay will produce a large number of products, each with a slightly different size, indicating a polyclonal population.  If a large number of cells harbor the same rearrangement of TCRG gene segments, the PCR product produced from these cells will be in much greater concentration than those produced from a polyclonal cell population, thus resulting in a "predominant" PCR amplicon size.  This is taken as evidence of a monoclonal population. 

Methodology: Polymerase chain reaction and capillary get electrophoresis

Limitations: Positive results are highly suggestive of malignancy; however, a positive result should not be used as the sole criterion for diagnosis. Both positive and negative results should be interpreted in the context of all clinical and laboratory findings. Up to 20% of T cell neoplasms can yield a false-negative result in this assay. Thus, a negative result with this assay cannot be used to exclude a T cell neoplasm.

This test was developed and its performance characteristics determined by the UC San Diego Health System Clinical Genomics Laboratory. It has not been cleared or approved by the US Food and Drug Administration. FDA clearance or approval is not required for clinical use. The result of this test should be interpreted using all relevant clinical data and should not be used alone for clinical diagnosis or patient management decisions.

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