Which size of needle is most likely to cause coring?

Coring is a process that occurs when the tip of a needle dislodges a piece of rubber or other material from the stopper of a vial, leading to contamination of the medication. The likelihood of coring is primarily influenced by the diameter of the needle used.

Larger gauge needles, such as a 13 G, have a wider lumen, which increases the risk of causing coring when they penetrate the rubber stopper of a vial. The greater surface area and pressure exerted by a large needle can more easily displace rubber particles compared to smaller needles. In contrast, smaller gauge needles, like the 23 G or even the 20 G, exert less pressure and are less likely to core the vial when inserted.

Therefore, using a 13 G needle significantly raises the potential for coring due to its large size, making it the correct answer to the question. Understanding this risk is crucial for maintaining the integrity of sterile preparations in both hospital and retail pharmacy settings.