When administering a purified protein derivative (PPD) for TB testing, what should the nurse ensure?

When administering a purified protein derivative (PPD) for tuberculosis (TB) testing, it is essential to ensure that the injection produces a wheal on the skin. The PPD is administered intradermally, and a small volume of the solution is injected just beneath the top layer of the skin. This technique is critical because the formation of a wheal confirms that the PPD has been correctly placed in the intradermal space, which allows for the appropriate local immune response to the test.

The wheal, which is a raised, swollen area at the injection site, indicates that the vaccine has been injected properly and can elicit an immune reaction if the person has been previously sensitized to the tuberculosis bacteria. This reaction typically appears as a localized induration, which is assessed 48 to 72 hours after administration.

Other considerations, such as the depth of injection or massaging the site, are not appropriate in this context. For a PPD test, the injection should not be administered deeply into the muscle, should not be massaged after injection, and there is no requirement for the client to remain in a supine position during or after the procedure. Thus, ensuring the formation of a wheal is the correct and crucial step