What type of injection is an intradermal (ID) injection primarily used for?

An intradermal (ID) injection is primarily used for testing for disease exposure, especially in the context of certain diagnostic tests. This method allows for the administration of a very small amount of substance, such as an allergen or tuberculin, just below the epidermis, which is the outer layer of skin. The location of the injection is crucial as it enables the immune response to be monitored in a controlled environment.

For example, the tuberculin skin test (Mantoux test) is a widely recognized intradermal method used to determine if someone has been exposed to the bacteria that cause tuberculosis. The localized immune response to the injected antigen can be assessed by checking for an induration at the injection site after a set period.

While other options may involve injections, they do not align with the unique characteristics and applications of intradermal injections, which focus on small volumes and shallow administration to stimulate a local immune response rather than broader systemic effects or fluid draws.