Terminal Deoxynucleotidyl Transferase Test

TdT is a marker to identify existence of cancer in blood cells known as leukemia. Terminal Deoxynucleotidyl Transferase (TdT) is a template-independent DNA polymerase that catalyzes the repetitive addition of deoxyribonucleotides to the 3'-OH of oligo-deoxyribonucleotides and single-stranded and double-stranded DNA. TdT is a highly specific marker for the diagnosis and classification of acute lymphoblastic lymphoma (ALL) or leukemia. The test is used to classify certain Leukemia and lymphomas, normally used to distinguish lymphoblastic from non-lymphoblastic leukemia, diagnose acute lymphoblast leukemia, lymphoid blast crisis of chronic myelogenous leukemia, and lymphoblastic lymphomas.

This test requires taking your blood sample. Blood will be taken from your arm. So it is advisable to wear a something with short sleeves, sleeves of which can be rolled up easily. You do not need to restrict your food and fluids or alter your diet before this test, You can eat, drink normally. Make sure you tell your doctor about any specific medication you are taking. Always follow specific instructions given to you by lab. You may experience slight discomfort due to needle puncture. Please keep calm, it’s natural.

TdT positivity can be helpful in confirming a diagnosis of lymphoblastic lymphoma or leukemia. Acute myeloid leukemias can also express TdT. TdT positive cases of blast phase CML correlate with a positive response to chemotherapy vincristine and prednisone. TdT-positive cells are found in small numbers in healthy lymph nodes and tonsils, the malignant cells of acute lymphoblastic leukaemia are also TdT-positive, and the antibody can, therefore, be used as part of a panel to diagnose this disease and to distinguish it from, for example, small cell tumors of childhood.

Seven to eight milliliters say; one to two teaspoons of a blood sample would be obtained directly from you. As elastic band will be wrapped around your upper arm to stop the flow of blood and make the veins visible. Area of skin where needle is to be inserted will be cleaned using alcohol Needle will be injected in the vein which is visible. A tube will be attached to the needle to fill it with blood, and blood will be transferred to vessel labeled with your name A gauze pad or cotton ball will be put over the needle site as the needle is removed. If skin swells apply warm press to the needle site.