Intro to Phlebotomy Techniques

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 When using a syringe inserted into the line, blood must be withdrawn slowly to avoid hemolysis.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.
PROCEDURE FOR VEIN SELECTION:

  • Palpate and trace the path of veins with the index finger. Arteries pulsate, are most elastic, and have a thick wall. Thrombosed veins lack resilience, feel cord-like, and roll easily.
  • If superficial veins are not readily apparent, you can force blood into the vein by massaging the arm from wrist to elbow, tap the site with index and second finger, apply a warm, damp washcloth to the site for 5 minutes, or lower the extremity over the bedside to allow the veins to fill.
PERFORMANCE OF A VENIPUNCTURE:

  • Approach the patient in a friendly, calm manner. Provide for their comfort as much as possible, and gain the patient’s cooperation.
  • Identify the patient correctly.
  • Properly fill out appropriate requisition forms, indicating the test(s) ordered.
  • Verify the patient’s condition. Fasting, dietary restrictions, medications, timing, and medical treatment are all of concern and should be noted on the lab requisition.
  • Check for any allergies to antiseptics, adhesives, or latex by observing for armbands and/or by asking the patient.
  • Position the patient. The patient should either sit in a chair, lie down or sit up in bed. Hyperextend the patient’s arm.
  • Apply the tourniquet 3-4 inches above the selected puncture site. Do not place too tightly or leave on more than 2 minutes (and no more than a minute to avoid increasing risk for hemoconcentration). Wait 2 minutes before reapplying the tourniquet.
  • The patient should make a fist without pumping the hand.
  • Select the venipuncture site.
  • Prepare the patient’s arm using an alcohol prep. Cleanse in a circular fashion, beginning at the site and working outward. Allow to air dry.
  • Grasp the patient’s arm firmly using your thumb to draw the skin taut and anchor the vein. The needle should form a 15 to 30 degree angle with the surface of the arm. Swiftly insert the needle through the skin and into the lumen of the vein. Avoid trauma and excessive probing.
  • When the last tube to be drawn is filling, remove the tourniquet.
  • Remove the needle from the patient’s arm using a swift backward motion.
  • Press down on the gauze once the needle is out of the arm, applying adequate pressure to avoid formation of a hematoma.
  • Dispose of contaminated materials/supplies in designated containers.
  • Mix and label all appropriate tubes at the patient bedside.
  • Deliver specimens promptly to the laboratory.


 

PHLEBOTOMY PROCEDURE ILLUSTRATED:

 

PERFORMANCE OF A FINGERSTICK:

  • Follow the procedure as outlined above for greeting and identifying the patient. As always, properly fill out appropriate requisition forms, indicating the test(s) ordered.
  • Verify the patient’s condition. Fasting, dietary restrictions, medications, timing, and medical treatment are all of concern and should be noted on the lab requisition.
  • Position the patient. The patient should either sit in a chair, lie down or sit up in bed. Hyperextend the patient’s arm.
  • The best locations for fingersticks are the 3rd (middle) and 4th (ring) fingers of the non-dominant hand. Do not use the tip of the finger or the center of the finger. Avoid the side of the finger where there is less soft tissue, where vessels and nerves are located, and where the bone is closer to the surface. The 2nd (index) finger tends to have thicker, callused skin. The fifth finger tends to have less soft tissue overlying the bone. Avoid puncturing a finger that is cold or cyanotic, swollen, scarred, or covered with a rash.
  • Using a sterile lancet, make a skin puncture just off the center of the finger pad. The puncture should be made perpendicular to the ridges of the fingerprint so that the drop of blood does not run down the ridges.
  • Wipe away the first drop of blood, which tends to contain excess tissue fluid.
  • Collect drops of blood into the collection device by gently massaging the finger. Avoid excessive pressure that may squeeze tissue fluid into the drop of blood.
  • Cap, rotate and invert the collection device to mix the blood collected.
  • Have the patient hold a small gauze pad over the puncture site for a couple of minutes to stop the bleeding.
  • Dispose of contaminated materials/supplies in designated containers.
  • Label all appropriate tubes at the patient bedside.
  • Deliver specimens promptly to the laboratory.

FINGERSTICK PROCEDURE ILLUSTRATED:

 


 

ADDITIONAL CONSIDERATIONS:

To prevent a hematoma:

  • Puncture only the uppermost wall of the vein
  • Remove the tourniquet before removing the needle
  • Use the major superficial veins
  • Make sure the needle fully penetrates the upper most wall of the vein. (Partial penetration may allow blood to leak into the soft tissue surrounding the vein by way of the needle bevel)
  • Apply pressure to the venipuncture site
To prevent hemolysis (which can interfere with many tests):

  • Mix tubes with anticoagulant additives gently 5-10 times
  • Avoid drawing blood from a hematoma
  • Avoid drawing the plunger back too forcefully, if using a needle and syringe, or too small a needle, and avoid frothing of the sample
  • Make sure the venipuncture site is dry
  • Avoid a probing, traumatic venipuncture
  • Avoid prolonged tourniquet application or fist clenching.
Indwelling Lines or Catheters:

  • Potential source of test error
  • Most lines are flushed with a solution of heparin to reduce the risk of thrombosis
  • Discard a sample at least three times the volume of the line before a specimen is obtained for analysis
Hemoconcentration: An increased concentration of larger molecules and formed elements in the blood may be due to several factors:

  • Prolonged tourniquet application (no more than 1 minute)
  • Massaging, squeezing, or probing a site
  • Long-term IV therapy
  • Sclerosed or occluded veins
Prolonged Tourniquet Application:

  • Primary effect is hemoconcentration of non-filterable elements (i.e. proteins). The hydrostatic pressure causes some water and filterable elements to leave the extracellular space.
  • Significant increases can be found in total protein, aspartate aminotransferase (AST), total lipids, cholesterol, iron
  • Affects packed cell volume and other cellular elements
  • Hemolysis may occur, with pseudohyperkalemia.
Patient Preparation Factors:

  • Therapeutic Drug Monitoring: different pharmacologic agents have patterns of administration, body distribution, metabolism, and elimination that affect the drug concentration as measured in the blood. Many drugs will have “peak” and “trough” levels that vary according to dosage levels and intervals. Check for timing instructions for drawing the appropriate samples.
  • Effects of Exercise: Muscular activity has both transient and longer lasting effects. The creatine kinase (CK), aspartate aminotransferase (AST), lactate dehydrogenase (LDH), and platelet count may increase.
  • Stress: May cause transient elevation in white blood cells (WBC’s) and elevated adrenal hormone values (cortisol and catecholamines). Anxiety that results in hyperventilation may cause acid-base imbalances, and increased lactate.
  • Diurnal Rhythms: Diurnal rhythms are body fluid and analyte fluctuations during the day. For example, serum cortisol levels are highest in early morning but are decreased in the afternoon. Serum iron levels tend to drop during the day. You must check the timing of these variations for the desired collection point.
  • Posture: Postural changes (supine to sitting etc.) are known to vary lab results of some analytes. Certain larger molecules are not filterable into the tissue, therefore they are more concentrated in the blood. Enzymes, proteins, lipids, iron, and calcium are significantly increased with changes in position.
  • Other Factors: Age, gender, and pregnancy have an influence on laboratory testing. Normal reference ranges are often noted according to age.

 


 

SAFETY AND INFECTION CONTROL

Because of contacts with sick patients and their specimens, it is important to follow safety and infection control procedures.
PROTECT YOURSELF

  • Practice universal precautions:
    • Wear gloves and a lab coat or gown when handling blood/body fluids.
    • Change gloves after each patient.
    • Wash hands frequently.
    • Dispose of items in appropriate containers.
    • Use a new tourniquet for each patient
    • Prep patients antecubital fossa using
  • Dispose of needles immediately upon removal from the patient’s vein. Do not bend, break, recap, or resheath needles to avoid accidental needle puncture or splashing of contents.
  • Clean up any blood spills with a disinfectant such as freshly made 10% bleach.
  • If you stick yourself with a contaminated needle:
    • Remove your gloves and dispose of them properly.
    • Squeeze puncture site to promote bleeding.
    • Wash the area well with soap and water.
    • Record the patient’s name and ID number.
    • Follow institution’s guidelines regarding treatment and follow-up.
    • NOTE: The use of prophylactic zidovudine following blood exposure to HIV has shown effectiveness (about 79%) in preventing seroconversion
PROTECT THE PATIENT

  • Place blood collection equipment away from patients, especially children and psychiatric patients.
  • Practice hygiene for the patient’s protection. When wearing gloves, change them between each patient and wash your hands frequently. Always wear a clean lab coat or gown.

 


 

TROUBLESHOOTING GUIDELINES:

IF AN INCOMPLETE COLLECTION OR NO BLOOD IS OBTAINED:

  • Change the position of the needle. Move it forward (it may not be in the lumen)
  • or move it backward (it may have penetrated too far).
  • Adjust the angle (the bevel may be against the vein wall).
  • Loosen the tourniquet. It may be obstructing blood flow.
  • Try another tube. Use a smaller tube with less vacuum. There may be no vacuum in the tube being used.
  • Re-anchor the vein. Veins sometimes roll away from the point of the needle and puncture site.
  • Have the patient make a fist and flex the arm, which helps engorge muscles to fill veins.
  • Pre-warm the region of the vein to reduce vasoconstriction and increase blood flow.
  • Have the patient drink fluids if dehydrated.
IF BLOOD STOPS FLOWING INTO THE TUBE:

  • The vein may have collapsed; resecure the tourniquet to increase venous filling. If this is not successful, remove the needle, take care of the puncture site, and redraw.
  • The needle may have pulled out of the vein when switching tubes. Hold equipment firmly and place fingers against patient’s arm, using the flange for leverage when withdrawing and inserting tubes.

PROBLEMS OTHER THAN AN INCOMPLETE COLLECTION:

  • A hematoma forms under the skin adjacent to the puncture site – release the tourniquet immediately and withdraw the needle. Apply firm pressure.Hematoma formation is a problem in older patients.
  • The blood is bright red (arterial) rather than venous. Apply firm pressure for more than 5 minutes.

 


 

BLOOD COLLECTION ON BABIES:

  • The recommended location for blood collection on a newborn baby or infant is the heel. The diagram below indicates in green the proper area to use for heel punctures for blood collection:
  • Prewarming the infant’s heel (42 C for 3 to 5 minutes) is important to obtain capillary blood gas samples and warming also greatly increases the flow of blood for collection of other specimens. However, do not use too high a temperature warmer, because baby’s skin is thin and susceptible to thermal injury.
  • Clean the site to be punctured with an alcohol sponge. Dry the cleaned area with a dry cotton sponge. Hold the baby’s foot firmly to avoid sudden movement.
  • Using a sterile blood lancet, puncture the side of the heel in the appropriate regions shown above in green. Do not use the central portion of the heel because you might injure the underlying bone, which is close to the skin surface. Do not use a previous puncture site. Make the cut across the heelprint lines so that a drop of blood can well up and not run down along the lines.
  • Wipe away the first drop of blood with a piece of clean, dry cotton. Since newborns do not often bleed immediately, use gentle pressure to produce a rounded drop of blood. Do not use excessive pressure or heavy massaging because the blood may become diluted with tissue fluid.
  • Fill the capillary tube(s) or micro collection device(s) as needed.
  • When finished, elevate the heel, place a piece of clean, dry cotton on the puncture site, and hold it in place until the bleeding has stopped.
  • Be sure to dispose of the lancet in the appropriate sharps container. Dispose of contaminated materials in appropriate waste receptacles. Remove your gloves and wash your hands.

HEELSTICK PROCEDURE ILLUSTRATED:

 


BELOW ARE SOME OF THE COLLECTION TUBES THAT ARE USED FOR PHLEBOTOMY.  THIS IS NOT THE ORDER OF DRAW!!!!!! JUST A REVIEW OF THE TUBES

 

COLLECTION TUBES FOR PHLEBOTOMY

Red Top
ADDITIVE None
MODE OF ACTION Blood clots, and the serum is separated by centrifugation
USES Chemistries, Immunology and Serology, Blood Bank (Crossmatch)
Gold Top
ADDITIVE None
MODE OF ACTION Serum separator tube (SST) contains a gel at the bottom to separate blood from serum on centrifugation
USES Chemistries, Immunology and Serology
Light Green Top
ADDITIVE Plasma Separating Tube (PST) with Lithium heparin
MODE OF ACTION Anticoagulates with lithium heparin; Plasma is separated with PST gel at the bottom of the tube
USES Chemistries
Purple Top
ADDITIVE EDTA
MODE OF ACTION Forms calcium salts to remove calcium
USES Hematology (CBC) and Blood Bank (Crossmatch); requires full draw – invert 8 times to prevent clotting and platelet clumping
Light Blue Top
ADDITIVE Sodium citrate
MODE OF ACTION Forms calcium salts to remove calcium
USES Coagulation tests (protime and prothrombin time), full draw required
Green Top
ADDITIVE Sodium heparin or lithium heparin
MODE OF ACTION Inactivates thrombin and thromboplastin
USES For lithium level, use sodium heparin
For ammonia level, use sodium or lithium heparin
Dark Blue Top
ADDITIVE EDTA-
MODE OF ACTION Tube is designed to contain no contaminating metals
USES Trace element testing (zinc, copper, lead, mercury) and toxicology
Light Gray Top
ADDITIVE Sodium fluoride and potassium oxalate
MODE OF ACTION Antiglycolytic agent preserves glucose up to 5 days
USES Glucoses, requires full draw (may cause hemolysis if short draw)
Yellow Top
ADDITIVE ACD (acid-citrate-dextrose)
MODE OF ACTION Complement inactivation
USES HLA tissue typing, paternity testing, DNA studies
Yellow – Black Top
ADDITIVE Broth mixture
MODE OF ACTION Preserves viability of microorganisms
USES Microbiology – aerobes, anaerobes, fungi
Black Top
ADDITIVE Sodium citrate (buffered)
MODE OF ACTION Forms calcium salts to remove calcium
USES Westergren Sedimentation Rate; requires full draw
Orange Top
ADDITIVE Thrombin
MODE OF ACTION Quickly clots blood
USES STAT serum chemistries
Light Brown Top
ADDITIVE Sodium heparin
MODE OF ACTION Inactivates thrombin and thromboplastin; contains virtually no lead
USES Serum lead determination
Pink Top
ADDITIVE Potassium EDTA
MODE OF ACTION Forms calcium salts
USES Immunohematology
White Top
ADDITIVE Potassium EDTA
MODE OF ACTION Forms calcium salts
USES Molecular/PCR and bDNA testing

 


 

References

Kiechle FL. So You’re Going to Collect a Blood Specimen: An Introduction to Phlebotomy, 13th Edition (2010), College of American Pathologists, Northfield, IL.Dalal BI, Brigden ML. Factitious biochemical measurements resulting from hematologic conditions. Am J Clin Pathol. 2009 Feb;131(2):195-204.Lippi G, Salvagno GL, Montagnana M, Franchini M, Guidi GC. Phlebotomy issues and quality improvement in results of laboratory testing. Clin Lab. 2006;52(5-6):217-30.

Lippi G, Blanckaert N, Bonini P, Green S, Kitchen S, Palicka V, Vassault AJ, Mattiuzzi C, Plebani M. Causes, consequences, detection, and prevention of identification errors in laboratory diagnostics. Clin Chem Lab Med. 2009;47(2):143-53.

Valenstein PN, Sirota RL. Identification errors in pathology and laboratory medicine. Clin Lab Med. 2004 Dec;24(4):979-96, vii.