Unit 5 - Phlebotomy and Capillary Puncture PDF

Unit 5: Phlebotomy, Capillary Puncture and Blood Glucose Measurement Learning Objectives Explain the importance of correct patient identification; complete specimen labeling; and proper handling, storage and delivery Demonstrate proper tourniquet placement and palpation of veins...

Unit 5: Phlebotomy, Capillary Puncture and Blood Glucose Measurement Learning Objectives Explain the importance of correct patient identification; complete specimen labeling; and proper handling, storage and delivery Demonstrate proper tourniquet placement and palpation of veins Summarize the step-by-step procedure for drawing blood with a syringe, vacuum tube system, butterfly or capillary puncture Perform venipuncture using butterfly needle system Choose appropriate blood collection tubes in proper order of draw List various reactions a patient might have to venipuncture Explain how to obtain capillary blood specimens for glucose testing Perform quality control testing on automated glucose analyzer Explain the concept of the hemoglobin A1c test and contrast it with daily glucometer testing Phlebotomy Phlebotomy aka venipuncture is used to acquire blood for testing A phlebotomist is a person trained to obtain blood specimens by venipuncture and capillary puncture techniques How the medical assistant is involved in phlebotomy will vary from one facility to another The MA performing venipuncture will have direct contact with the patient and will leave an impression with the patient The MA must display professionalism by performing tasks in an efficient, competent manner; wearing clean, neat attire; and showing concern for patients and their feelings The Circulatory System The heart pumps blood through the body by way of vessels – the arteries, veins and capillaries When blood flows away from the heart it flows in arteries Blood flowing back to the heart flows through the veins Tiny capillaries connect the arteries (and smaller arterioles) with the veins (and smaller venules) Arteries and Veins Arteries Veins Carry blood from the Carry blood to the heart, heart, carry oxygenated carry deoxygenated blood (except pulmonary blood (except pulmonary artery) vein) The blood is normally The blood is normally bright red dark red Elastic walls that expand Thin walls/less elastic with surge of blood No valves Valves Can feel a pulse No pulse Plasma, Serum and Whole-Blood The body contains approximately 6 L of blood 45% of which is formed elements – erythrocytes, leukocytes and thrombocytes 55% of the blood is liquid – known as plasma Blood also contains fibrinogen – that is converted to fibrin during the clotting process Clear, straw-colored liquid that is left after the clot is formed is called serum – used for many tests in the lab Plasma contains fibrinogen – Serum does not Plasma, Serum and Whole-Blood Collection Most laboratory tests are performed on serum, plasma or whole blood The formed elements and the liquid (serum or plasma) are usually separated for Venipuncture Sites The preferred site for venipuncture is the antecubital space Here the veins are near the surface and are large enough to give access to the blood The median cubital vein is used the majority of the time If not available palpate other veins in the antecubital space Basilic, Cephalic and Median When necessary, veins on the dorsal surface of the hand or wrist may be used The veins of the feet are an alternative when the arms are not available Venipuncture Equipment Gauge Comments Syringes Size Needles 23 Used sometimes with butterfly system Vacuum Tubes 22 Preferred for pediatrics or very small veins Anticoagulants, Additives and Gels 21 Most common size with vacuum tubes Tourniquets 20 Appropriate, but large Specimen Collection Trays for common phlebotomy 18 Not used for phlebotomy, sometimes used for blood banking/donations 16 Most commonly used in blood banking/donations Method Indications for Use Advantages Disadvantages Vacuum Routine collection Fast May not work well tube Multiple tubes are needed Relatively safe with: Whenever possible Best specimen quality Small/Fragile veins Large collection amount Difficult draws possible Small children Hand or Feet draws Butterfly Small or fragile veins Least likely to collapse Syringe attachment Difficult draws vein not as safe because Small children or older Less painful to patient tube transfer is adults Can attach syringe necessary Can attach vacuum tube Specimen may adapter become hemolyzed Least likely to pass Not recommended through small veins for large amounts of Good specimen quality blood Syringe Children, Infants, Older Easier to perform Not recommended Adults, Oncology patients, Allows for smaller amount for dehydrated Severely burned patients, of specimen patients Obese patients, Not recommended inaccessible veins, for patients with extremely fragile veins, poor circulation when specimen requires a Cannot be used for: Blood Collection Tubes – Red and Light Green Light Green Top Red Top Contains: Plasma separating Contains: None tube (Na Heparin) Effects on Specimen: Blood Effects on specimen: clots, and the serum is Anticoagulants with lithium separated by centrifugation heparin; plasma is separated Uses: Chemistries, with PST gel at the bottom of immunology and serology, the tub blood bank Chemistries Blood Collection Tubes – Red-Gray Mottled and Lavender/Purple Red-Gray Mottled Top Contains: Serum separating Lavender/Purple Top tubes (SST) with clot Contains: EDTA (liquid form) activator Effects on specimen: Forms Effects on specimen: Forms calcium salts to remove clot quickly and separates calcium the serum with SST gel at Uses: Hematology (CBC) and the bottom of the tube blood bank; requires a full Uses: Blood type screening draw – invert 8 times to and chemistries prevent clotting and platelet clumping Blood Collection Tubes – Gold and Light Blue Light Blue Contains: Sodium citrate (Na Gold Top Citrate) Contains: Separating gel and Effects on specimen: Forms clot activator calcium salts to remove Effects on specimen: Serum calcium separator tube (SST) Uses: Coagulation tests (PT, contains a gel at the bottom PTT, TCT, CMV) tube must be to separate the blood from filled 100% serum on centrifugation Uses: Serology, endocrine, immunology, including HIV testing Blood Collection Tubes – Dark Green and Yellow Dark Green Top Contains: Sodium heparin or Yellow Top lithium heparin Contains: ACD (acid-citrate- Effects on specimen: dextrose) Inactivates thrombin and Effects on specimen: thromboplastin Complement inactivation Uses: Ammonia, lactate, HLA Uses: paternity testing, DNA typing, For lithium level use studies sodium heparin For ammonia level use sodium or lithium heparin Blood Collection Tubes – Dark Blue, Orange and Tan/Brown Dark Blue Top Orange Top Contains: Sodium heparin or Contains: Thrombin Na2 EDTA Effects on specimen: Quickly Effects on specimen: Forms clots blood calcium salts; tube is Uses: STAT serum designed to contain no chemistries contaminating metals Uses: toxicology and trace Tan/Brown Top element testing (zinc, Contains: Sodium heparin copper, lead, mercury) and Effects on Specimen: drug level testing Inactivates thrombin and thromboplastin Uses: Serum lead determination Blood Collection Tubes – Light Gray and Black Light Gray Top Contains: Sodium fluoride Black Top and potassium oxalate Contains: sodium citrate Effects on specimen: (buffered) antiglycolytic agent Effects on specimen: Forms preserves glucose up to 5 calcium salts to remove days calcium Uses: For lithium level use Uses: Westergren sodium heparin; Glucose sedimentation rate; requires requires a full draw (may a full draw cause hemolysis if short draw) Order of Draw Blood culture tubes or vials Yellow top or culture bottles Sodium citrate Light blue top Serum tubes Red top and Red/Gray and Gold top Heparin tubes Green tops, light and dark EDTA tubes Lavender top, then pink, white or royal blue Glycolytic inhibitor Gray top Fibrin degradable products Dark blue Venipuncture Principles Put the Patient at Ease Use therapeutic communication Prepare Supplies Have everything within reach Identify Patient and Specimen Identify patient by full name and DOB Label specimens completely and accurately Position the Patient The best position is the most comfortable for the patient and the MA Select the Appropriate Vein Check the antecubital region of the arm first Applying the Tourniquet Place 3 to 4 inches above the intended puncture site and is tight enough to block blood flow from veins The tourniquet should be on the arm no longer than 1 minute Performing a Safe and Successful Venipuncture Find the site that will give you the best blood return Rely on touch; while you practice close your eyes will palpating Trace the vein and feel for turns If no veins become prominent release tourniquet and change arms If the “vein” has a pulsing action it is an artery Tendons can be deceptive and give the appearance of veins but will not be bouncy Stimulate the vein Position the patient’s arm lower than his or her heart Massage the arm from the wrist to the elbow to encourage venous return Tap sharply at the specific vein with your fingertips. This can cause the vein to dilate Warm the site with a warming device or a warm washcloth Have the patient make a first; Do not have them pump the fist Do not subject the patient to more than 2 attempts After 2 attempts ask another health care professional to try The Syringe Technique Used less often than the vacuum tube method Ideal for collecting small volumes of blood from fragile, thin or “rolling” veins or veins on the back of the hand Pulling on the plunger of the syringe creates suction https://youtu.be/INes_0nYH58 Vacuum Tube Specimen Collection Quicker and allows for multiple tubes to be drawn The vacuum is already in the tube Vacuum tube holder is held in a manner that allows tubes to be changed without switching hands https://youtu.be/_8ZsqXFqvQM Butterfly Needle Collection System Allows for either a syringe draw or a vacuum tube draw Used for small, fragile veins that are difficult to puncture with the vacuum tube system Also works well on children who have small veins and the tendency to move while blood is being collected https://youtu.be/_w3-gtzvenk Patient Reactions to Blood Draws Patients can have a variety of reactions to having their blood drawn The MA must anticipate these reactions and respond appropriately The most common patient reactions are fear and pain Ask the patient if he or she has had blood drawn in the past Other reactions can include syncope/fainting or nausea Factors Affecting Laboratory Results Factor Effect Factor Effect Blood A nonalcohol-based antiseptic Diurnal Some specimens must be drawn Alcohol should be used to clean the site. Rhythm at timed intervals because of The cleansing alcohol may falsely med or diurnal (daily) rhythm. elevate the test result The exact time must be noted on label Exercise Strenuous short-term exercise Fasting If patient is not in fasting state can make the heart work harder when fasting is required, test and increase cardiac enzymes results will be inaccurate Hemoly Caused by not allowing alcohol to Heparin Using the incorrect heparin sis air-dry and site, using a needle additive can interfere with tests that is too small, focing blood into being run on the patient a tube from a syringe, or shaking instead of mixing gently Stress Violent crying before collection Tournique Hemoconcentration can occur, can increase the WBC count t on too causing a change in chemical long concentration Volume Not enough blood will cause a dilution factor Capillary Puncture Capillary puncture is a method of obtaining one to several drops of blood for a variety of tests Tests such as CBC, RBC count, WBC count, Hgb, and Hct, blood glucose, PKU, etc. Tests that CANNOT be run on capillary blood include: sedimentation rates, blood cultures, and coagulation studies Method of choice for 2 types of patients Patient blood volume is a concern (ex. Infants) Patient with difficult vein access (ex. scarred or burned patients) Capillary Puncture The usual site for capillary puncture is the fingertip In adults the ring finger is often selected In infants the lateral or medial plantar surface of the heel pad is used Area selected must be carefully prepared Site must be warm – increase circulation by gentle massage or apply a warm, moist towel or pack for 3 to 5 minutes Alcohol-soaked gauze should be used to cleanse Puncture is made at the tip of the fleshy pad and slight to the side Wipe away the first drop of blood Blood is collected in capillary tubes or other capillary collecting devices Do not squeeze the fingertip https://youtu.be/ibU5PYOF2qg Blood Glucose Glucose serves as an energy source for the body. Excess glucose is converted into glycogen for short-term storage in the liver and muscle cells and as adipose tissue for long- term storage Tests for blood glucose levels are commonly performed in the medical office Used to screen for carbohydrate disorders such as hypoglycemia and hyperglycemia both of which can occur in DM A variety of testing methods have been developed to diagnose, evaluate and monitor abnormalities in carbohydrate metabolism. Fasting Blood Glucose and Two-Hour Postprandial Blood Glucose Test Fasting Blood Glucose Commonly used to screen for DM Normal fasting value of glucose ranges from 70 to 110 mg/dL A value of 120 mg/dL is the dividing point between healthy and hyperglycemic individuals Two-Hour Postprandial Blood Glucose Not used to diagnose diabetes but is useful in evaluating appropriate insulin dosage Pt takes insulin with a meal than exactly two hours after the meal begins check blood glucose level In a healthy person the glucose has returned to normal An elevated 2-hour postprandial test may indicate that insulin needs adjusting Hemoglobin A1c HbA1c or glycosylated hemoglobin determination is a blood test that measures an average of glucose in the blood over the past few months This value gives providers a better picture of how well the diabetic patient has maintained a healthy serum glucose level Does not indicate whether the patient has experience hyperglycemia or hypoglycemia over the time frame so it is not useful in adjusting insulin Patient does not have to fast for this test Normal: Less than 5.7% without diabetes Less than 7.0% with diabetes Oral Glucose Tolerance Test Provides more detailed information that can be used to assess insulin response to glucose and to diagnose diabetes Often used to diagnose gestational diabetes These measurements help determine the patient’s ability to deal with increased glucose After fasting for 8 hours the patient is given a glucose solution Glucose levels are tested every 30 to 60 minutes for 3 to 6 hours During the test the patient must not ingest anything Patient can not smoke or chew gum either During the second and third hours of the test the patient may experience weakness, slight faintness and perspiration – this is normal! BG usually peaks 30 to 60 mins after consumption at 160 to 180 mg/dL and returns to the fasting level after 2 to 3 hours Patients with diabetes will still have increased glucose levels at the end of the test Automated Methods of Glucose Analysis Several types of glucose analyzers are available that are suitable for POLs Example – DCS 2000 is a common HbA1c analyzer Glucose controls are purchased to check instrument performance Each glucometer is different so it is important to use test materials that are made for a particular instrument The MA is sometimes responsible for providing education to patients on how to use glucometers, including maintenance and calibration of the meters Using an Automated Glucose Analyzer Checking a patient’s blood glucose level https://youtu.be/j4vf3Xn-6Ag Performing control checks on glucometer https://youtu.be/hjX9rSehJm8