T-Cell Clonality (T-Cell Receptor Gamma (TCRG)) Gene Rearrangements

CPT Code(s):

  • 81342
  • 88381 (FFPE)

Specimen Requirements:

  • Paraffin-embedded tissue; send one tissue block or 4 unstained slides. Ship specimens at 20° – 25° C. Tissue fixed in formalin substitute and/or that does not contain lymphocytes is unacceptable.
  • Blood or bone marrow in EDTA or ACD tube; one 3 mL blood or 1 mL bone marrow shipped at 4° C is accepted. Severely hemolyzed whole blood or clotted/frozen blood/bone marrow specimens are not accepted.
  • Tissue with a minimum size of 5 mm cube, shipped frozen or on ice in RPMI 1640, is accepted.
  • Cell pellets with at least 1 million cells, shipped at 4° C, are acceptable.


This test is used to demonstrate clonality in T-cell lymphomas/leukemias.


Polymerase chain reaction/DNA fragment analysis


5 – 10 business days

Reference Values:


Interpretation Data:

Positive: A monoclonal T-cell population is detected.
Negative: A monoclonal T-cell population is not detected.
Undetermined: Refer to interpretation notes.
QNS: There is not sufficient material to perform the test

TCR gene rearrangements are detected by using a multiplex PCR master mix, which contains 4 primers from the conserved V region that are clustered into 4 families (I-IV) and 4 primers from the J region. The primers cross the hyper variable antigen binding CDR region (Clonality is determined by analyzing bands on gel electrophoresis.).

A false negative may be due to:
  1. The clonal population being under the test limitation;
  2. Poor sample quantity (an inadequate amount of tissue);
  3. Poor sample quality (such as degraded DNA with paraffin-embedded specimen); and/or
  4. A small amount of the tumor not being detected by this assay.