Final answer:
When performing a venipuncture for blood collection, the patient's arm should be extending outward and positioned downward beneath the collection bag to utilize gravity for blood flow.
Step-by-step explanation:
When performing a venipuncture, the arm should be extended outwards and positioned downward for blood collection, while for intravenous (IV) fluid administration, the site of entry should be below the IV bag.
This is because for blood collection, gravity helps facilitate blood flow from the arm into the bag. Conversely, for IV fluid administration, the bag must be placed at least 0.24 m above the entry point to allow fluids to enter the arm. The use of an inflatable cuff, often associated with blood pressure measurement, is not directly related to venipuncture positioning but is another procedure that also requires specific arm positioning at the level of the heart.