What type of injection should be given at a 15-degree angle without aspiration?

A subcutaneous injection is administered at a 15-degree angle because this angle allows the needle to enter the subcutaneous tissue, which is the layer of fat just beneath the skin. This technique minimizes discomfort for the patient and ensures that the medication is delivered to the appropriate area for absorption. Aspiration, which is the practice of pulling back on the plunger to check for blood return, is not necessary with subcutaneous injections. This is because the needle is unlikely to penetrate a blood vessel in the subcutaneous tissue, reducing the risk of complications and making the process more efficient for administering medications such as insulin or certain vaccines.

The other types of injections mentioned either require different angles or techniques, or involve direct access to veins or muscle tissue, where aspiration might be a more critical step. For example, intramuscular injections would typically be administered at a 90-degree angle to ensure that the medication is delivered deep into the muscle.