The Venipuncture Procedure

Posted by jenaisle on February 23, 2010

The venipuncture or phlebotomy procedure is one method of blood collection that allows multi-collection with a larger volume of blood.  You can do it with the use of a syringe or a vacutainer whichever you find easier. Not anyone can perform a venipuncture because of some complications that can occur in the process.  Skilled phlebotomists or Medical Technologists usually perform the procedure.

photo by Fatima Al Ribh

Materials needed

Sterile and dry syringe

Sterile dry cotton

Sterile wet cotton

Test tubes

Needle

Test tube rack

Labeling tape

Pentel pen or labeling pen

Parafilm

Tourniquet

Procedure

Step 1

Prepare your materials by arranging them in an area within your arm’s reach. Check the needle and syringe if they are working well, by pulling and pushing the plunger and examining the needle. Do not remove the cap of the needle unnecessarily.

Step 2

Select the most appropriate site of puncture. A vein that is not too small or too big is ideal. Big veins have the propensity to roll and small veins are less likely visible.  Take time in your selection process. The most common site of puncture is the antecubital fossa at the bend of the arm.  There are three veins you could select from, the cephalic, basilica and mid-cubital veins.

Step 3

When you have selected the best vein, sterilize it in a circular motion, starting from the site of puncture going outwards.  Do not reuse dirty cotton. Sterilize until clean.

Step 4

Let it dry for a few seconds and with your syringe and needle, puncture the site smoothly and deliberately.  There should be no hesitation, as this would inflict more pain to the patient. Enter the vein in one smooth movement.

Step 5

As blood enter the hub of the needle, pull the plunger smoothly taking care not to pull the needle out of the vein.

Step 6

After you have drawn the required amount of blood, withdraw the needle smoothly, not too fast, nor too slow to avoid severing the vein.

Step 7

Apply pressure to the wound for about 3-5 minutes.  You could allow the patient to do it, if he cannot, then apply micropore.  Be sure to check the wound after 5 minutes to make certain that there is no bleeding.

Step 8

Remove the needle from the syringe and transfer the blood to a test tube by allowing the blood to flow at the sides of the tube to avoid hemolysis. Be sure that your test tube is also dry and clean to avoid hemolysis and contamination. Cover the tube and label it properly.

Step 9

Dispose your used materials properly into appropriate trash bags or cans. Clean your working area properly,

Step 10

Check the wound of the patient and thank him/her for cooperating.

Tips on Preventing Hemolysis

Posted by jenaisle on February 22, 2010

In the laboratory, it is crucial that the clinical laboratory scientist performs the tests reliably, because the doctor bases his diagnosis on these laboratory results. Any source of error therefore is eliminated to ensure that all results are accurate. One source of unreliable results is hemolysis.   Hemolysis is the destruction or rupture of red blood cells (RBCs) causing the release of hemoglobin.   An indication of hemolysis is a pink colored serum or plasma.

Here are pointers to avoid hemolysis in blood samples.

1. Do not use wet materials because water is a hypotonic solution that causes lysis of RBCs.

2. Do not squirt blood directly into the test tube. The rapid flow may cause hemolysis. Allow the blood instead to ooze at the sides of the tube.

3. Remove the needle before transferring the blood to appropriate containers, the small opening of the needle may cause hemolysis.

4. Do not centrifuge blood if it still has not clotted properly.

5. Do not rim or ring the blood several times. This is one major source of hemolysis.

6. Do not freeze whole blood right after collection.

7. Do not vigorously shake whole blood, to avoid hemolysis in blood samples.

8. Do not expose the whole blood specimen to excessively low and hot temperatures.

9. Do not prolong tourniquet application more than necessary.

10.  Transfer the serum immediately to a different container to reduce the propensity for hemolysis.

11.  Do not pull the plunger too quickly. If the bore of the needle is small, it may cause hemolysis

12.   Allow the site to dry first after sterilization.  The alcohol still present in the area may come in contact with your sample and may produce hemolysis.

13.  There should be a proper angle of the needle to the vein to avoid transfixation, which may cause hemolysis.

14.  Any application of mechanical trauma or pressure on the blood sample will cause hemolysis, whether during collection, processing, or transportation.

Avoid hemolysis in blood samples at all cost, as this would produce unreliable results.  Unreliable results would lead to misdiagnosis. Misdiagnosis by the doctor because of your inaccurate results would endanger the life of the patient.  Remember these pointers on how to avoid hemolysis in blood samples and feel confident and secure that you are giving out your best service to patients.  Consider each patient as an important individual who deserves to  receive reliable results.