Intradermal injections are primarily used for what purpose?

Intradermal injections are primarily used for skin testing purposes, such as allergy testing or tuberculosis screening. This technique involves injecting a small amount of substance into the dermis, the layer of skin just below the outer epidermis. The reason for this method is that it allows for a localized immune response to be observed, which is vital for assessing reactions to allergens or infectious agents.

Unlike intramuscular or subcutaneous injections that are designed for larger volumes and systemic absorption of medications, intradermal injections are specifically tailored to deliver a very small volume (typically less than 0.5 mL). The response to an intradermal injection can be monitored closely for signs of an allergic reaction or infection over time, making it a crucial technique in clinical settings for diagnostic purposes. This distinct function differentiates it from the other techniques mentioned.