Final answer:
The nurse should instruct the client to return to the clinic in 2 or 3 days for the reading of the Mantoux tuberculin skin test. A positive test indicates exposure to TB and is not necessarily indicative of active TB. The test involves a single needle injection, not skin scratching.
Step-by-step explanation:
When providing teaching for a client who is to have a tuberculin skin test, it is important to include that they must return to the clinic to have the test read in 2 or 3 days. The Mantoux tuberculin skin test involves the subcutaneous injection of a purified protein derivative of the tuberculosis bacteria. The site of injection should initially produce a raised wheal, and after 48-72 hours, the test will be read, with a positive result indicated by redness, swelling, or hardness of the responding region.
A positive result on the tuberculin skin test does not necessarily mean the patient has an active case of tuberculosis (TB). It indicates that the patient has been exposed to the bacteria and exhibits a cellular immune response to it. This exposure may have been recent, or years prior, as the test measures the reactivation of memory T cells. Additional tests, such as chest radiographs, may be needed to confirm an active infection.
Another critical point to emphasize is that a positive test result does not lead to another TB skin test in 3 weeks and that unlike the historical method of scarification, the Mantoux test does not involve using a lancet to scratch the skin but instead uses a single needle injection.