T-cell Receptor Beta (TRB) Clonality Detection by PCR and Capillary Electrophoresis
CPT Code(s)
[4:16 PM] David, Marjorie P 81340, G0452
Synonym(s)
TCR Beta Gene Clonality Detection, T-cell Receptor (TCR) Beta Gene Rearrangement, PCR, TCRB
Performed
Molecular Diagnostics Laboratory
Clinical Indication and Relevance
The assay is useful to assist with the diagnosis of T-cell malignancies. The assay can also be used to detect minimal residual disease in follow-up samples.
Methodology
DNA is isolated and amplified by PCR using BIOMED-2 primers targeting Vß, Dß and Jß sequences. The gene rearrangements are detected by analyzing the PCR products by capillary gel electrophoresis. The assay sensitivity for detection of clonal T-cell populations is 10% of lymphocytes.
Minimum Specimen Requirements
Collect
- Peripheral blood (PB): 3-5 mL, in purple top (sodium EDTA) tube.
- Bone marrow (BM): 1-3 mL, drawn into a syringe containing anticoagulant and then
delivered in purple top tube (EDTA). - Fresh or frozen tissue: fresh tissue should be obtained in a sterile manner, and a minimum
3 mm3
of tissue is required. Fresh tissue should be placed in culture medium for transport
or snap frozen (see transport section below). - Formalin-fixed, paraffin-embedded (FFPE) tissue blocks: send tissue block to the lab, or
contact lab for instructions regarding cutting paraffin sections for molecular studies.
Transport
- PB or BM sample: Deliver immediately at 2-8°C (wet ice or cold packs). Do not freeze.
- Fresh tissue samples should be delivered at room temperature in RPMI culture medium within 3 hours of collection, or snap frozen in liquid nitrogen at -70°C and packed in
dry ice for delivery. Please do not allow frozen tissues to thaw. - Formalin-fixed paraffin embedded (FFPE) tissue blocks and slides can be delivered at controlled temperatures, not to exceed 30C.
Stability
PB or BM samples: ambient – 1 hour; refrigerated – 48 hours.
Unacceptable Samples
- Serum or plasma; frozen PB or BM; clotted blood; severely hemolyzed samples
- Paraffin tissue fixed in Zenker’s, B5, or Bouin’s fixatives
- Bone marrow biopsy decalcified in formic acid
Turnaround time
Five to seven working days
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