Of the following needle sizes, which is most likely to cause coring?

Coring refers to a situation where a core or a piece of rubber is removed from a vial stopper when a needle is inserted, which can contaminate the medication and pose a risk to patients. The likelihood of coring increases with larger needle sizes because they create larger holes.

In this case, the 13 G needle is the largest diameter among the options provided. The larger the gauge number, the smaller the diameter; thus, a 13 G needle is significantly larger than the others listed. When a large needle is used, the risk of damaging the vial stopper material increases, leading to a higher chance of coring.

Smaller needle sizes, such as 20 G or 23 G, are less likely to cause this issue since they are designed to create smaller entry points, which reduces the risk of tearing or dislodging a core from the stopper. Therefore, using a smaller gauge needle typically minimizes the risk of coring when accessing medication vials.