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 must a permit-holder wait before making an appointment for a driving test? Once you earn your learner's permit, you may be forced to wait an allotted amount of time before you can take your driving test. Some states allow you to schedule an appointment in advance, but you must usually wait 120 to 180 days before taking the test. This delay varies by state, and you should consult your local department of motor vehicles for specific requirements and instructions.