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.
How long is the independent driving part of the test. How long this part of the driving test lasts depends on traffic conditions. Generally, the independent part of the test last for around 10 minutes and will often include roundabouts, junctions, and crossroads of all types.