Final answer:
For the administration of contrast medium via venipuncture, the veins of the arms are the preferred injection sites due to their accessibility and lower risk of complications. A 25 gauge needle is typically too small for such procedures, and while both immediate and delayed reactions to contrast media can occur, this statement is not inherently true across all cases.
Step-by-step explanation:
When venipuncture is performed for contrast medium administration, the veins of the arms are indeed preferred injection sites. The rationale behind this preference is related to the anatomy of the veins. The median cubital vein, part of the superficial veins of the upper limb, is a commonly chosen site for it is easily accessible and presents less risk for complications. Although a smaller gauge needle may theoretically reduce the risk of extravasation (leakage of fluid into the surrounding tissue), a 25 gauge needle is generally considered too small for the administration of contrast medium due to its viscosity; typically, a larger gauge needle is preferred. Regarding reactions, while an immediate reaction to the contrast medium can occur, delayed reactions are also possible.
Considering this information, the correct statement would be: 'The veins of the arms are preferred injection sites for venipuncture when administering contrast medium.' The other options provided are not necessarily true in general clinical practice. Lastly, while venous catheters are often necessary for the long-term administration of medications or fluids and can be life-saving, they are also associated with risks such as bloodstream infections, underscoring the importance of using proper techniques and precautions during venipuncture procedures.