Blood specimens should not be collected from an arm into which intravenous (IV) fluid is being administered. If at all possible, the phlebotomist should draw blood from the opposite arm or hand. If an IV line is delivering fluid into the patient's vein and the specimen is drawn from that vein, the specimen may be contaminated and diluted by the IV fluid; the blood test results could then be erroneous.
If the arm or hand opposite of the arm that contains the IV line is not accessible or cannot be used for another reason, a capillary collection may be an option, if only a small amount of specimen is needed. However, if a venipuncture is necessary and the arm that has the IV line in place is the only option, ask the clinical person in charge of the patient's care to turn off the patient's IV. Ensure that the fluid has stopped flowing through the line, and wait at least two minutes before performing the venipuncture. It is imperative that the phlebotomist witness that the IV has physically been turned off by the health care provider and then turned back on after the draw has been completed. A phlebotomist must not turn the IV on or off.