The Test Sample
What is being tested?
T-cells are a type of lymphocyte (a kind of white blood cell, WBC) that helps to protect the body from infection. Rearrangements in certain parts of their DNA called receptor genes are a normal part of their development. These rearrangements are associated with the development of a large repertoire of diverse T-cells, allowing them to protect against many different kinds of infections. The final order in which the genes are rearranged is called a gene rearrangement profile. Within any normal population (sample) of T-cells, the cells and their gene rearrangement profiles are very diverse.
In lymphoma, the T-cells in affected tissue (such as blood, lymph node, or skin) are identical and their gene rearrangement profiles are likewise identical. Lymphomas arise when an abnormal T-cell begins to produce numerous identical copies of itself (clones). The cloned cells grow and divide uncontrollably, crowding out normal cells.
A T-cell receptor gene rearrangement test evaluates the T-cells in a person's sample to determine whether the majority of T-cell rearrangement profiles are diverse or identical. This information, along with clinical signs and symptoms and results of other laboratory tests, can help clarify a person's diagnosis, or evaluate for persistent or recurrent lymphoma.
Most non-Hodgkin lymphomas in the U.S. are B-cell lymphomas (about 85%), according to the American Cancer Society. Close to 15% are T-cell lymphomas. There are many different types of T-cell lymphomas, but each is rare.
For additional details about T-cells and this testing, read more.
How is the sample collected for testing?
A bone marrow, lymph node, or other tissue biopsy procedure is performed by a doctor or other trained specialist. Body fluid samples are obtained through collection of the fluid in a container by inserting a needle into the body cavity and aspirating a portion of the fluid with a syringe. Sometimes, a blood sample is obtained by inserting a needle into a vein in the arm.
NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.
Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.
Is any test preparation needed to ensure the quality of the sample?
No test preparation is needed.