T-Cell Receptor Gene Rearrangement, PCR, Blood

Casandra

Casandra Test Code MC92422Version 1 (DRAFT)

Performing Lab

Lab Mayo Clinic LabLab Test ID TCGRCPT Codes 81340, 81342

T-Cell Receptor Gene Rearrangement, PCR, Blood

Clinical Use

Use

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). This marked diversity is vital for normal immune functions but also helps distinguish abnormal T-cell proliferations from reactive processes. A monoclonal expansion of a T-cell population results in a single TCR-gene rearrangement pattern, detectable by molecular techniques like PCR. This test is useful for determining if a T-cell population is monoclonal or polyclonal using blood specimens.

Special Instructions

Include relevant clinical information and cytogenetic results, if available. The test must arrive within 7 days of collection. If not ordering electronically, a Hematopathology/Cytogenetics Test Request form should be completed and sent with the specimen.

Limitations

The detection of a clonal TCR-gene rearrangement is not necessarily indicative of a T-cell neoplasm. False-positive results can occur due to the sensitivity of PCR and nonuniform (skewed) amplification of target T-cell gene rearrangements. This issue can be due to a limited total T-cell number in a sample or physiological skewing of the T-cell repertoire, as seen in aging, post-transplantation, or immune reactions in autoimmune or nonlymphoid malignancies. False negatives can also occur due to poor amplification or failure to detect a minority of T-cell gene segment rearrangements with consensus PCR primers.

Test Details

New York Approved