Final answer:
The Mantoux test requires an intradermal injection for the screening of tuberculosis, with readings taken between 48-72 hours after administration.
Step-by-step explanation:
The medical assistant should use the intradermal route for the Mantoux test. This test involves injecting a small amount of tuberculin material just below the surface of the skin, which typically produces a raised wheal. The test should be read in 48-72 hours, with a positive result indicated by redness, swelling, or hardness in the area of the injection. The injection is typically administered on the inside of the forearm, and the test is read 48-72 hours later to determine the presence of a positive result.