Phlebotomy

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Phlebotomy is a procedure that consists of venipuncture and withdrawal of blood. It is a safe outpatient method where blood is extracted from the vein through a cut or puncture. This procedure is performed by a nurse or technician called phlebotomist.

Purpose

Phlebotomy is performed for many reasons which include the following:

1. To obtain sample for analysis and diagnosis.
2. To treat polycythemia. Polycythemia is a condition where elevation or red blood cell volume is noted. Part of the treatment of this disorder is carrying out therapeutic phlebotomy.
3. To decrease the total blood volume of patients with pulmonary edema.
4. To remove blood from the body during blood donation.
5. To analyze blood substances contained in blood before clearing a person for blood donation.

Safety Guidelines

• Universal precautions are used with this procedure. Gloves should be worn when performing this procedure.
• Prior to blood collection it is important that the one performing the procedure is properly trained and identified as licensed phlebotomist.
• Properly identify your patient. Check the name tag and verify with the patient or nurse on duty.
• Supplies should be checked for their integrity.
• Label vials and tubes properly. Indicate date and time of extraction with the name of the patient clearly indicated.
• Needles should be immediately disposed in an approved sharps container. They never be recapped and should only be used once.
• Assess the patient for complications associated with the phlebotomy procedure.

Venipuncture Site Selection:

Although the larger and fuller median cubital and cephalic veins of the arm are used most frequently, the basilic vein on the dorsum of the arm or dorsal hand veins are also acceptable for venipuncture. Foot veins are a last resort because of the higher probability of complications.

Certain areas are to be avoided when choosing a site:

• Extensive scars from burns and surgery - it is difficult to puncture the scar tissue and obtain a specimen.
• The upper extremity on the side of a previous mastectomy - test results may be affected because of lymphedema.
• Hematoma - may cause erroneous test results. If another site is not available, collect the specimen distal to the hematoma.
• Intravenous therapy (IV) / blood transfusions - fluid may dilute the specimen, so collect from the opposite arm if possible. Otherwise, satisfactory samples may be drawn below the IV by following these procedures:
  
  • Turn off the IV for at least 2 minutes before venipuncture.
  • Apply the tourniquet below the IV site. Select a vein other than the one with the IV.
  • Perform the venipuncture. Draw 5 ml of blood and discard before drawing the specimen tubes for testing.
• Lines - Drawing from an intravenous line may avoid a difficult venipuncture, but introduces problems. The line must be flushed first. When using a syringe inserted into the line, blood must be withdrawn slowly to avoid hemolysis.
• Cannula/fistula/heparin lock - hospitals have special policies regarding these devices. In general, blood should not be drawn from an arm with a fistula or cannula without consulting the attending physician.
• Edematous extremities - tissue fluid accumulation alters test results.

Description of Procedure

In this procedure, blood is extracted from a vein on the back of the hand or over the antecubital fossa. However, some tests require blood to be taken from an artery. In blood transfusion, donors are placed in a semirecumbent position and the skin over the antecubital fossa is carefully cleansed with an iodine preparation or antiseptic solution. A tourniquet or elastic band is applied around the arm to retain blood in the area and make the veins visible. After the phlebotomist selects an appropriate vein for blood extraction, venipucture is performed. – A needle is inserted into the vein and the tourniquet is released.

The appropriate amount of blood to be withdrawn widely varies. Blood donation and therapeutic phlebotomy require larger amount of blood than blood analysis. Blood donors usually give about 450 to 500 ml of blood per session. For laboratory analysis, the volume of blood needed depends on the type of test performed. Approximately, one or more 5 to 10 ml tubes of blood are withdrawn.

Withdrawal of 450 ml of blood takes less than 15 minutes. After the needle is removed, the donor is asked to hold the involved arm straight up and apply firm pressure on the site with sterile gauze for about 2 to 3 minutes or until the bleeding stops. The phlebotomy technician then places a bandage on the site.

Instructions After the Procedure

• Within 1 to 2 minutes the donor is asked to remain in the position until they feel able to sit up. If weakness or faintness is experienced, the donor should rest for a longer time.
• Foods and fluids are given when the donor sits up and is asked to remain for another 15 minutes.
• Heavy lifting should be avoided for several hours.
• Smoking should be avoided for an hour.
• Alcoholic beverages should be avoided for 3 hours.
• For 2 days, fluid intake should be increased and balanced diet should be practiced for 2 weeks.

NOTE: Always observe aseptic technique to protect your patient and yourself.