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.
Use:
This test is used to demonstrate clonality in T-cell lymphomas/leukemias.
Methodology:
Polymerase chain reaction/DNA fragment analysis
Reported:
5 - 10 business days
Reference Values:
Negative
Performed:
Monday - Friday
Interpretation Data:
| T-Cell Clonality |
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:
- The clonal population being under the test limitation;
- Poor sample quantity (an inadequate amount of tissue);
- Poor sample quality (such as degraded DNA with paraffin-embedded specimen); and/or
- A small amount of the tumor not being detected by this assay.