Test Name: TdT

Methodology: Flow Cytometry

Test Description

Staining for terminal deoxynucleotidyl transferase (TdT) highlights normal precursor B-cells in bone marrow, tonsils and lymph nodes and normal thymocytes. TdT is expressed by the blasts in most cases of B and T-lymphoblastic lymphoma/leukemia, 10-15% of cases of acute myeloid leukemias, some mixed lineage leukemias and some non-hematopoietic neoplasms (Merkel cell carcinoma).

Specimen Requirements

Testing for this antigen is typically performed as a part of the acute leukemia add-on panel. For customized testing panels including this antigen, please contact the Medical Director of the Flow Cytometry laboratory.

Storage and Transport

Maintain specimen at room temperature. Do not refrigerate or freeze. Use cold pack for transport, making sure cold pack is not in direct contact with specimen.

Specimen Rejection Criteria

Click here to reference the specimen rejection criteria.

Turn Around Time (TAT): 24 hours

CPT Codes*: 88184, 88185, 88187, 88188, 88189

*The CPT codes provided with our Test Descriptions are based on AMA guidelines and are for informational purposes only. Correct CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed.