The collection of blood from veins is called venipuncture. For the convenience of technician and patient, arm veins are best for obtaining a blood sample. If arm veins cannot be used due to interference from bandage or IV therapy, thrombosed or hardened veins, etc., consult your supervisor for instructions on the use of hand or foot veins.

NOTE: Do not draw blood from an arm with IV fluid running into it. Choose another site. The IV fluid will alter tests results.

Materials Required for Venipuncture Procedure

To perform a venipuncture, the following materials are required:

Sterile gauze pads (2" x 2")
70% isopropyl alcohol or povidone-iodine solution pads

Tourniquet
needles and holder
tube appropriate for the test to be performed

Arrange your equipment in an orderly manner and have it within easy reach. Also, wash your hands before the procedure.

Venipuncture Procedure
Position the patient so that the vein is easily accessible and you are able to perform the venipuncture in a comfortable position. Always have the patient either lying in bed or sitting in a chair with the arm propped up.

Figure 7-3.-Finger puncture.

WARNING
Never perform a venipuncture with the patient standing up. If patients should faint, they could seriously injure themselves. Also, safeguards should be in place to prevent patients from falling forward when they are seated.

To perform venipuncture, follow the steps given below.

1. Explain the procedure to the patient.
2. Apply tourniquet around the arm approximately 2 to 3 inches above the antecubital fossa (the depression in the anterior region of the elbow, see figure 7-4) with enough tension so that the VEIN is compressed, but not the ARTERY. A BP cuff (sphygmomanometer) may be used instead of a tourniquet if a patient is difficult to draw.

3. Position the patient's arm extended with little or no flexion at the elbow.

4. Locate a prominent vein by palpation (feeling). If the vein is difficult to find, it may be made more prominent by massaging the arm with an upward motion to force blood into the vein.

5. Cleanse the puncture site with a 70% alcohol pad or povidone-iodine solution and allow to dry.

CAUTION: After cleaning the puncture site, only the sterile needle should be allowed to touch it.

6. "Fix" or hold the vein taut. This is best accomplished by placing the thumb under the puncture site and exerting a slight downward pressure on the skin or placing the thumb to the side of the site and pulling the skin taut laterally (fig. 7-4).

7. Using a smooth continuous motion, introduce the needle, bevel side up, into the side of the vein at about a 15-degree angle with the skin (fig. 7-4).

8. Holding the barrel with one hand, push the tube into the holder with the other hand and watch for the flow of blood into the tube until filling is completed.

9. Once all the specimens have been collected, hold the with one hand and release the tourniquet with the other.

10. Place a sterile gauze over the puncture site and remove the needle with a quick, smooth motion.

11. Apply pressure to the puncture site and instruct the patient to keep the arm in a straight position. Have the patient hold pressure for at least 3 minutes.

12. Take this time to invert any tubes that need to have anticoagulant mixed with the blood.

13. Label specimens.
14. Reinspect the puncture site to make sure bleeding has stopped, and apply a bandage.

Figure 7-4.-Venipuncture.