Venipuncture Technique Using a Syringe
When Using a Syringe with Needle is Preferred
Some phlebotomists prefer to use the syringe and needle technique for their venipunctures. If this system is used the blood specimen can be transferred from the syringe directly into the vacuum tube which then will be sent to the reference lab. However, whenever blood is transferred by this method specific safety measures must be applied and strictly adhered to.
Drawing Blood with a Syringe
REMEMBER: Whether you choose between the evacuated tube system or the syringe system to collect blood, safety holders (preferably disposable), safety needles, safety blood transfer devices and shields are mandatory and required under Occupational Safety and Health Agency (OSHA) guidelines!
The needle to be used should be a safety needle. It should be #21 gauge or larger in order to facilitate rapid flow into and out of the syringe and thus minimize hemolysis. Disposable needles are used routinely. Make sure you briefly inspect the needle to make sure it is free of any nicks and damage.
If one standard size of syringe is used, the 20 mL size is recommended in order to accommodate larger amounts of specimen required for some procedures. Inspect syringe by moving the plunger within the barrel to ensure free movement. NOTE: Disposable plastic syringes are required.
After assembly of the syringe and needle unit, move plunger within unit to ensure syringe patency.
Cleanse venipuncture site with an appropriate antiseptic, usually betadine or 70% isopropyl alcohol, using circular motion towards the periphery. Allow area to dry before proceeding. The reason is two-fold: it prevents the burning sensation for patient when venipuncture is performed and it prevents hemolysis of the blood.
If phlebotomy site must be palpated again it can only be done with one finger that was cleansed with alcohol before touching to feel the vein.
Apply tourniquet around arm 3-4 inches above venipuncture site. Do not leave tourniquet on the arm for more than 1-2 minutes.
Grasp patient's arm firmly, placing the thumb 1-2 inches below the chosen site to draw skin taut. This will anchor the vein. If possible, make sure the patient's arm is in a downward position. This will help ensure that no back-flow from the tube will go into the patient's arm.
Perform venipuncture entering the vein keeping bevel side of needle up.
Grasp the barrel of syringe firmly and pull firmly on plunger until required amount of blood is in the syringe.
Ask patient to open fist and remove tourniquet as soon as desired amount of blood has been obtained. Remember not to release tourniquet until blood collection is completed.
Lightly place gauze or cotton pad upon venipuncture site.
At the completion of the venipuncture, immediately after the needle is removed from the vein apply direct pressure to puncture site.
Ask patient keep arm fully extended, elevate arm and with the other hand apply pressure over puncture site for a few minutes. Check site for bleeding. If site is still bleeding, continue direct pressure. Do not bandage until bleeding has completely stopped. Once bleeding has stopped, apply bandage over the gauze pad at site. Advise patient to leave bandage on for 15 minutes.
Using a syringe to collect blood dictates the need for transferring the collected blood to a test tube before disposing of the contaminated blood collection device. After the blood specimen has been collected a safety transfer device for transferring blood from a syringe to vacuum tubes or blood culture bottles should be used.
One example of such a safety transfer device is the BD Blood Transfer Device
You can read usage tips and view a video here!
Remove the needle from the arm, activate the safety feature, remove and discard the needle and attach the hub of the syringe to the safety transfer device. The purpose of various brands of safety transfer devices on the market is to ensure health care worker safety during the transfer of blood from a syringe into an evacuated tube or blood culture bottle. Their design resembles a modified tube holder that has an interior needle to pierce the stopper thus preventing accidental needle sticks, spillage, and exposure!
Whenever safety needles and safety transfer device as Occupational Safety and Health Agency (OSHA) requires are available they should be used. Phlebotomists should visit the OSHA web site for the latest information!
Alternative Technique of Blood Sample Transfer
Because this web site is visited by an international audience where available equipment, techniques, safety rules and regulations may be different from those required in the United States of America we opt to discuss an alternate, but less safe technique of transferring a collected blood sample from a syringe to evacuated tubes for transport. We need to point out that any and all individuals with blood drawing responsibilities should be familiar with their country's, state, and local laws, and adhere to their particular workplace practices and safety standards.
When drawing blood always be conscious of safety measures!
- After the blood sample is obtained leave the needle on the syringe and insert it through the rubber stopper into the vacuum tube.
- Do not hold vacuum tube with your hand! Stand the tube in a test tube rack while inserting the syringe's needle.
- There is no need to push down on the plunger, just allow the vacuum to draw the specimen from the syringe.
- Never forcefully eject the collected blood from the syringe into the vacuum tube.
The pressure behind plunger that forces the blood through the needle combined with the force with which it is ejected out of the needle into the tube may result in hemolysis or worse, may cause the stopper to pop off creating a spray of blood droplets or the vacuum tube may explode causing spillage and danger of exposure to blood and bloodborne pathogens!