The nurse is preparing to administer an intradermal injection.
Which angle should the nurse insert the needle?

Choice A rationale

An intradermal injection is administered into the dermis, the layer of skin directly beneath the epidermis. A 15-degree angle ensures the needle enters superficially, creating a small wheal as the medication is deposited. This shallow angle minimizes penetration into subcutaneous tissue, which is crucial for proper antigen-antibody reactions in allergy testing or tuberculosis screening.

Choice B rationale

A 90-degree angle is used for intramuscular injections, where the medication is delivered deep into muscle tissue. This angle allows for rapid absorption due to the rich vascular supply of muscle, but it would cause excessive penetration and potential systemic absorption if used for an intradermal injection, negating its diagnostic purpose.

Choice C rationale

A 45-degree angle is typically used for subcutaneous injections, delivering medication into the adipose tissue layer beneath the dermis. This angle is too deep for an intradermal injection and would result in the medication being absorbed systemically rather than remaining in the dermal layer for localized diagnostic reactions.

Choice D rationale

A 30-degree angle is also too steep for an intradermal injection. While less deep than a 45-degree angle, it still risks penetrating beyond the dermis into the subcutaneous tissue. The goal of an intradermal injection is to deposit the substance within the highly specific dermal layer to elicit a localized, measurable response.