What is the primary reason the basilic vein is the last choice for blood collection?

The basilic vein is typically considered the last choice for blood collection mainly due to its proximity to cutaneous nerves. This anatomical feature poses a higher risk of damaging these nerves during venipuncture, which can lead to complications such as pain, numbness, or tingling in the arm. The basilic vein is located on the medial side of the arm, and its close relationship with nerve structures complicates its selection as a site for venipuncture.

Considering the other factors, while the vein being too superficial may seem like a disadvantage, there are other veins that can be accessed that are more superficial and safer. The lumen size of the basilic vein can vary, and while it may sometimes be smaller than other veins, that does not solely dictate its use. The propensity for the vein to collapse is a concern, yet it does not outweigh the significant risk associated with the nearby nerves. Thus, the close proximity to cutaneous nerves is the primary reason for minimizing the use of the basilic vein for blood draws.