Why is patient hydration important before blood collection?

Patient hydration is crucial before blood collection primarily because it helps engorge veins, making them more prominent and accessible for venipuncture. When a patient is well-hydrated, their blood volume increases, which leads to more distended veins. This distension makes it easier for phlebotomists to locate and successfully puncture a vein on the first attempt, reducing the likelihood of multiple needle sticks, which can cause discomfort and anxiety for the patient.

By contrast, dehydration can lead to difficulty in locating veins, which may require additional effort and time, and can potentially lead to discomfort and complications during the blood draw. This is why encouraging patients to hydrate, especially with clear fluids, is a routine practice before phlebotomy procedures.