T (Thymus Derived) Lymphocyte Count. Definition. T cells are a type of white blood cells (lymphocytes). They make up part of the immune system. T cells help the body fight diseases or harmful substances. A test can be done to measure the number of T cells in your blood. Thymus derived lymphocyte count; T-lymphocyte count.
The road test generally takes 15 to 20 minutes. 1  If you fail the road test you must wait a minimum of two weeks (14 days) before taking the road test again and must pay another $40 testing fee. 2  Test results are valid for 2 years. If you fail the road test you must wait a minimum of two weeks (14 days) before taking the road test again and must pay another $40 testing fee. 2  Test results are valid for 2 years.
The driving test as a whole takes an average of 20-30 minutes--sometimes less, sometimes more. It also depends on the amount of traffic on the route (more traffic generally means the test will go a little longer than usual). Relax, and don't worry too much about the time frame. My test lasted about 20 minutes, but it went by incredibly quickly.