1010 Unit 4 Text PDF

76 CHAPTER 4 LEARNING OUTCOMES At the conclusion of this chapter, the student will be able to: Identify eight factors that should be monitored by quality Describe the mode of action of assessment methods. ethylenediaminetet...

76 CHAPTER 4 LEARNING OUTCOMES At the conclusion of this chapter, the student will be able to: Identify eight factors that should be monitored by quality Describe the mode of action of assessment methods. ethylenediaminetetraacetate (EDTA) and heparin. Demonstrate the knowledge and skills needed to interact Identify the major potential type of error in specimen with patients when collecting specimens. collection. Explain the Patient Care Partnership and its importance. Assess the cause and formulate a solution to correct five Describe the characteristics of a phlebotomist specific situations that could complicate venipuncture site Interpret the principles and applications of Standard selection. Precautions. Name eight typical phlebotomy problems, and describe Describe the equipment used for venous blood collection. the solution for each problem. Arrange the proper steps in the collection technique for Explain some techniques for obtaining blood from small venous blood and analyze the outcomes, if the sequence or difficult veins. of steps is incorrect. Describe special blood collection considerations for Identify the color codes of evacuated tubes with the pediatric and geriatric patients. additives contained in the tubes. Categorize the symptoms of potential phlebotomy Compare common anticoagulants and additives used to complications and propose treatment for each type of preserve blood specimens and the general use of each complication. type of anticoagulant. Demonstrate and describe the proper technique for collecting a capillary blood specimen. KEY TERMS anticoagulant hematoma plasma capillary iatrogenic anemia postprandial dialysis icteric serum edema lipemic venipuncture fibrinogen phlebotomy Venous or arterial blood collection, phlebotomy, and QUALITY ASSESSMENT capillary blood collect remain an error-prone phase of the The term quality assessment, or the alternate term quality testing cycle. In the United States, it is estimated that more assurance, encompasses policies that maintain and control than 1 billion venipunctures are performed annually, and processes involving the patient and laboratory analysis of errors occurring within this process may cause serious harm specimens. Quality assessment includes monitoring the fol- to patients, either directly or indirectly (Table 4-1). Leading lowing specimen collection measures: causes of preanalytical errors include the following1: Preparation of a patient for any specimens to be 1. Specimen collection tube not filled properly collected 2. Patient identification error Collection of valid samples 3. Inappropriate specimen collection tube or container Proper specimen transport 4. Test request error Performance of the requested laboratory analyses Other types of potential preanalytical errors include Validation of test results hemolyzed specimens, blood clots caused by inadequate mix- Recording and reporting the assay results ing of evacuated collection tubes containing anticoagulant, Transmitting test results to the patient’s medical record and an insufficient volume of blood collected in an evacuated Documentation, maintenance, and availability of tube. An insufficient volume of blood in an evacuated tube records describing quality assessment practices and can result from air in the tubing line of a butterfly phlebot- quality control measures omy collection device. Air in the line must be removed by The accuracy of laboratory testing begins with the qual- initially collecting a small amount of blood in a discard tube ity of the specimen received by the laboratory. This quality before actual specimen collection. depends on how a specimen was collected, transported, and processed. A laboratory assay will be no better than the speci- Patient Care Partnership men on which it is performed. If a preanalytical error occurs, The delivery of health care involves a partnership between the most perfect analysis is invalid and cannot be used by the patients and physicians and other health care professionals. physician in diagnosis or treatment. When collecting blood specimens, it is important that the  Phlebotomy: Collecting and Processing Patient Blood Specimens 77 TABLE 4-1 Examples of Phlebotomy Pediatric Patients Preanalytical Errors When working with children, it is important to be gentle and compassionate. Attempt to interact with the pediatric patient, BEFORE PHLEBOTOMY AFTER realizing that both the patient and the parent (if present) may PHLEBOTOMY PROCEDURE PHLEBOTOMY have anxiety about the procedure and may be unfamiliar with Misidentified Excess tourniquet Improper transport the clinical setting. Acknowledge both the parent and the patient time or storage child. conditions Do not hurry; allow enough time for the procedure. It Wrong evacuated Incorrect order- Hemolysis caused is important to take extra time to gain a child’s confidence specimen tubes of-draw of by improper before proceeding with specimen collection. When working specimen mixing of blood with pediatric patients, it is important to bolster their morale with the additive as much as possible. Ask for help in restraining a very small or (shaking). Inadequate fasting Failure to gently Incorrect uncooperative child. Older children may be more responsive conditions invert specimen specimen- when permitted to “help” (for example by holding the gauze). collection tubes handling In the nursery, each hospital will have its own rules, but a several times, directions (such few general precautions apply. After working with an infant if the tube as improper in a crib, the crib sides must be returned to the precollection contains an centrifugation position. If an infant is in an incubator, the portholes should anticoagulant or or clot-contact be closed as much as possible. When oxygen is in use, do not additive time) forget to close the openings when the collection process is Not coordinated Underfilling completed. Dispose of all waste materials properly. with medication evacuated tubes Adolescent Patients Modified from Ernst DJ: Applied phlebotomy, Philadelphia, 2005, When obtaining a blood specimen from an adolescent, it Lippincott Williams & Wilkins, p 62. is important to be relaxed and alert to possible anxiety. Adolescents may mask their anxiety. General interaction phlebotomist consider the rights of the patient at all times. techniques include allowing enough time for the procedure, The American Hospital Association2 has developed the establishing eye contact, and allowing the patient to maintain Patient Care Partnership document, which replaces the former a sense of control. Patient’s Bill of Rights. This document stresses the following: High-quality hospital care Adult Patients A clean and safe environment Adult patients must be told briefly what is expected of them Involvement by patients in their care and what the test involves. Complete honesty is important. Protection of patients’ privacy The patient should be greeted in a friendly and tactful man- Help for patients when leaving the hospital ner. Without becoming overly familiar, a pleasant conver- Help for patients with billing claims sation can be started. The patient should be told about the Patients themselves or another person chosen by the purpose of the blood collection. Any personal information patient can exercise these patient rights. A proxy decision revealed by the patient is told in confidence. The patient’s maker can act on the patient’s behalf if the patient lacks religious beliefs should be respected, laboratory reports kept decision-making ability, is legally incompetent, or is a minor. confidential, and any personal information also kept in con- The partnership nature of health care requires that fidence. Information about other patients or physicians is patients—or their families or surrogates—take part in their always kept confidential. If the same patient is seen frequently, care. As such, patients are responsible for providing an accu- the phlebotomist may become familiar with the patient’s rate medical history and any written advance directives, fol- interests, hobbies, or family and use these as topics of con- lowing hospital rules and regulations, and complying with versation. Many patients in the hospital are lonely; kindness activities that contribute to a healthy lifestyle. is greatly appreciated. Occasionally, especially if extremely ill, the patient will not want to talk at all, and this should be The Phlebotomist respected. It is important to be honest but also attempt to The phlebotomist is a critically important member of the boost the patient’s morale as much as possible. laboratory team. In fact, the phlebotomist represents the Even if the patient is disagreeable, the phlebotomist laboratory to patients. It is important that the phlebotomist should remain pleasant. A smile can often work miracles. It project a professional image by wearing a clean, white lab coat is important to be firm when the patient is unpleasant, to with a visible name badge. Hair should be short or tied back remain cheerful, and to express confidence in the work to be with no dangling jewelry, nails should be short and clean, and done. proper shoes must be worn for safety reasons (see Chapter 2). In a hospital setting, before leaving the patient’s room, the The collection tray or work cubicle must be immaculate (see area should be checked to see that everything is in place in Specimen Collection). the laboratory tray and that the room has been left as it was 78 CHAPTER 4 found. The tray holding the blood collection supplies and A second tier of an infection control system was devel- equipment should always be kept out of reach of the patient. oped to provide additional precautions to control the trans- All sharps and supplies should be disposed of properly. mission of infectious agents under special circumstances when Standard Precautions alone may not be enough. Geriatric Patients Transmission-based precautions are divided into three basic It is extremely important to treat geriatric patients with dig- categories: contact, airborne, and droplet. nity and respect and not demean them. It is best to address the patient with a more formal title, such as Mrs., Ms., or Mr., Contact Precautions rather than by his or her first name. As with patients in general, Contact precautions are designed to stop the spread of micro- older patients may enjoy a short conversation. Keep a flexible organisms through direct contact, such as skin-to-skin contact, agenda so enough time is allowed. If a patient appears to be and indirect contact, which is usually the result of a person having difficulty hearing, speak slightly slower and louder. making contact with a contaminated inanimate object. Contact precautions include wearing gloves when making contact with Problem Patients the patient’s skin or with inanimate objects that have been in Occasionally, a patient will be combative. This may be the direct contact with the patient. The use of gowns may be man- result of alcohol ingestion, drug use, or a psychiatric condi- dated when the health care worker’s clothing is likely to come tion. In some of these cases, such as with mentally challenged in contact with the patient or items in the patient’s room. patients, the phlebotomist would need the written permis- sion of a parent, guardian, or conservator. This is the same Droplet Precautions requirement as drawing blood from a minor—a patient Droplet precautions protect health care workers, visitors, and younger than 18 years of age. Because injury to the patient other patients from droplets, which may be expelled during or the phlebotomist could result from performing a phlebot- coughing, sneezing, or talking. Guidelines include using a omy, a supervisor should be consulted. The supervisor could mask when working close to the patient. Guidelines for patient consult with the patient’s physician regarding how to proceed placement, from the use of a private room to using a room with this patient. with special air-handling capabilities, should be implemented as well. Specific guidelines for transport and placement of patients and the environmental management of equipment INFECTION CONTROL should be implemented according to each category’s require- ments. Droplet precautions are particularly important when Isolation as Safety System influenza or whooping cough is present. Isolation was once understood as the separation of a seriously ill patient to stop the spread of infection to others or to pro- Airborne Precautions tect the patient from irritating factors. The term isolation has Airborne precautions are designed to provide protection from changed from meaning a special set of precautions performed airborne bacteria or dust particles, which may be suspended by a few health care providers for a select few patients to a in the air for an extended period. Guidelines include the use safety system that is practiced by everyone in the course of of respiratory protection (such as N95 respirator) and the use routine patient care. Isolation precautions are now a routine of special air-handling systems to control airborne bacteria. part of the everyday work process. Airborne precautions must be observed when patients have Modern isolation techniques incorporate a broad-based measles or tuberculosis. theory that addresses the needs of both patients and employ- ees to ensure that the safest possible environment is main- tained throughout the health care facility. Current guidelines SPECIMEN COLLECTION use a two-tiered strategy to create this safety system. Blood is the type of specimen most frequently analyzed in the clinical laboratory. Urine specimens, body fluids, and stool Standard and Additional Precautions specimens are also frequently analyzed. Other specimens The concept of Standard Precautions forces health care pro- such as throat cultures and swabs from wound abscesses are fessionals to change the way they view infection control. sent to the microbiology laboratory for study. A two-tiered system has been developed, the goal of which Knowledge of proper collection, preservation, and processing is to minimize the risk of infection and maximize the safety of specimens is essential. A properly collected blood specimen is level within the health care facility’s environment. crucial to quality performance in the laboratory. In addition to The first tier of infection control is the practice of Standard specimen procurement, related areas of specimen transporta- Precautions. Standard Precautions theory recognizes the tion, handling, and processing must also be fully understood by need to reduce the risk of microbial transmission, including anyone who collects or handles blood specimens. human immunodeficiency virus (HIV), from both identi- Strict adherence to the rules of specimen collection is fied and unidentified sources of infection. These precautions critical to the accuracy of any test. Errors such as identifica- require that protective protocols be followed whenever con- tion errors, either of the patient or the specimen, are major tact is made with blood and body fluids. potential sources of error.  Phlebotomy: Collecting and Processing Patient Blood Specimens 79 Role of the Phlebotomist Immobilization (such as resulting from prolonged bed Blood specimens may be collected by health care personnel rest) with several different educational backgrounds, depending on Exercise the facility. In some institutions, blood specimen collection Circadian/diurnal variations (cyclical variations is done by the clinical laboratory scientist/medical technolo- throughout the day) gist or the clinical laboratory technician/medical laboratory Recent food ingestion (such as caffeine effect) technician. In other institutions, specially trained individuals, Smoking (nicotine effect) phlebotomists, perform blood collections. Alcohol ingestion The role of the phlebotomist has never been more import- ant to the patient and the laboratory. Phlebotomists in the Blood Collection Procedures hospital, clinic, or drawing station have a major impact on There are two general sources of blood for clinical labora- the impression that patients develop of the entire laboratory. tory tests: venous blood and peripheral (or capillary) blood. Phlebotomists are laboratory ambassadors. These members The Clinical and Laboratory Standards Institute (CLSI) has of the health care team must demonstrate professionalism by set standards for the collection of venous blood (venipunc- their conduct, appearance, composure, and communication ture, or phlebotomy) and capillary blood (skin puncture).4,5 skills. Critical thinking skills are essential for phlebotomists. Arterial blood may be needed to perform specific procedures They must make effective decisions and solve problems, fre- such as blood gas analysis. quently under conditions of stress.3 One specific area of improvement in laboratory test results Layers of Normal Anticoagulated Blood is improvement in the blood sample collection and analy- In vivo (in the body) the blood is in a liquid form, but in vitro sis process. The majority of laboratory errors are caused by (outside the body) it will clot in a few minutes. Blood that is mistakes before testing, or preanalytical errors. Errors in the freshly drawn into a glass tube appears as a translucent, dark- preanalytical phase involving phlebotomists can be reduced red fluid. In minutes it will start to clot, or coagulate, form- through appropriate professional training and constant vig- ing a semisolid jellylike mass. If left undisturbed in the tube, ilance in testing. this mass will begin to shrink, or retract, in about 1 hour. The phlebotomist is expected to deliver unexcelled cus- Complete retraction normally takes place within 24 hours. tomer satisfaction. It is important to understand and know Whole blood that is allowed to clot normally produces the patient’s expectations, manage unrealistic expectations a pale-yellow fluid called serum when it separates from the through patient education, and be diplomatic with patient clot and appears in the upper portion of the tube. During complaints. If a patient is dissatisfied, the phlebotomist the process of coagulation, certain factors present in the should listen with interest, express genuine concern, and original blood sample are depleted, or used up. Fibrinogen make an attempt to resolve the issue of concern. If the phle- is one important substance found in circulating blood botomist is directly at fault, an apology would be appropriate. (in the plasma portion) that is necessary for coagulation to occur. Fibrinogen is converted to fibrin when clotting Blood Collection Variables occurs, and the fibrin lends structure to the clot in the form Most clinical laboratory determinations are done on whole of fine threads in which the red blood cells (RBCs, eryth- blood, plasma, or serum. Blood specimens may be drawn from rocytes) and the white blood cells (WBCs, leukocytes) are fasting or nonfasting patients. The fasting state is defined as embedded. To assist in obtaining serum, collection tubes having no food or liquid other than water for 8 to 12 hours with a separator gel additive are used. Serum is used exten- before blood collection. Fasting specimens are not neces- sively for chemical, serologic, and other laboratory testing sary for most laboratory determinations. Blood from fasting and can be obtained from the tube of clotted blood by patients is usually drawn in the morning before breakfast. centrifuging. Blood collected directly after a meal is described as a When fresh whole blood is mixed with substances that postprandial specimen. In the case of blood glucose, a sam- prevent blood clotting, called an anticoagulant, the blood ple may be collected 2 hours postprandially. After 2 hours, can be separated into plasma, a straw-colored fluid, and the blood glucose levels should return to almost fasting levels in cellular components: erythrocytes, leukocytes, and platelets patients who are not diabetic. Blood should not be collected (thrombocytes). When an anticoagulated blood specimen is while intravenous (IV) solutions are being administered, if allowed to stand for a time, the components will settle into possible. three distinct layers (Fig. 4-1), as follows: Food intake, medication, activity, and time of day can all 1. Plasma, the top layer, a liquid that normally represents influence the laboratory results for blood specimens. It is about 55% of the total blood volume critically important to control preanalytical variables such as 2. Buffy coat, a grayish white cellular middle layer com- timed drawing of a specimen, peak and trough drug levels, posed of WBCs and platelets, normally about 1% of and postmedication conditions. Other controllable biological the total blood volume variations in blood include the following: 3. Erythrocytes, the bottom layer, consisting of packed Posture (whether the patient is lying in bed or stand- RBCs and normally about 45% of the total blood ing up) volume 80 CHAPTER 4 glass. Conditions of extremely high humidity could lead to the migration of water vapor inside a tube that contains a moisture-sensitive material, such as a lyophilized additive. Conditions of extremely low humidity could hasten the Plasma escape of water vapor from a tube containing a wet additive. 55% Water 90% Such storage conditions may compromise the accuracy of Solutes 10% clinical results. Light Leukocytes and A special additive mixture for coagulation testing that is sen- thrombocytes sitive to light and found only in glass evacuated tubes is called (platelets) CTAD (citric acid, theophylline, adenosine, and dipyrida- mole). The CTAD mixture minimizes platelet activation after Formed elements blood collection. Normally, this additive has a slightly yellow 45% Erythrocytes appearance that becomes clear when no longer viable. These tubes are generally packaged in small quantities to minimize exposure to light. FIGURE 4-1 Composition of blood. (Redrawn from Expiration Dates of Evacuated Tubes Applegate E: The anatomy and physiology learning system, Expiration dates are determined by testing shelf life under ed 4, St Louis, 2011, Elsevier/Saunders.) known environmental conditions. Shelf life of an evacuated tube is defined by the stability of the additive and vacuum retention. Most evacuated tubes on the market have at least a Environmental Factors Associated with 12-month shelf life. It is important that tubes be stored under Evacuated Blood Collection Tubes recommended conditions. A variety of environmental factors can affect the quality The expiration dates of glass tubes are generally limited of evacuated tubes used to collect blood. These factors can by the shelf life of the additives, because vacuum and water then influence the published expiration dates of the evacu- vapor losses are minimal over time. Exposure to irradiation ated tubes.6 Environmental factors affecting evacuated tubes during sterilization of tubes and to moisture or light during include the following: the shelf life of the product can limit the stability of biochem- Ambient temperature ical additives. The expiration dates of evacuated plastic tubes Altitude are also limited by the same factors that affect glass tubes. Humidity Evacuated plastic tubes do sustain a measurable loss of vac- Sunlight uum over time, and some evacuated plastic blood collection tubes may have their expiration dates determined by their Ambient Temperature ability to ensure a known draw volume. If evacuated tubes are stored at low temperature, the pressure It is important to understand that evacuated blood col- of the gas inside the tube will decrease. This would lead to an lection tubes are not completely evacuated. There is a small increase in draw volume for the evacuated tube. Conversely, amount of gas (air) still residing in the tube, at low pressure. higher temperatures could cause reductions in draw volume. The higher the pressure of the gas inside the tube on the date Increased temperatures in evacuated tubes can also have a of manufacture, the lower the intended draw volume will be negative impact on the stability of certain tube additives, such for a tube of a given size. The draw volume specified for a as biochemicals or gel. Gel is a compound that could poten- given tube is achieved by manufacturing the tube at a desig- tially degrade when exposed to high temperatures. nated evacuation pressure. The dynamics of blood collection inside the tube are based Altitude on the ideal gas law: In situations where blood is drawn at high altitudes (>5000 PV = nRT feet), the draw volume may be affected. Because the ambient pressure at high altitude is lower than at sea level, the pres- where P is the pressure inside the tube, V is the volume that sure of the residual gas inside the tube will reach this reduced the gas occupies, n is the number of moles of gas inside the ambient pressure during filling earlier than if the tube were tube, R is the universal gas constant, and T is the temperature drawn at sea level. The resulting draw volume will be lower. inside the tube. According to the equation, if the moles of gas and the tem- Humidity perature do not change, the product of pressure and volume The impact of storage under different humidity conditions is a constant. When blood starts filling the tube, the residual can affect only plastic evacuated tubes because of the greater gas inside is confined into a decreasing volume, causing the permeability of these materials to water vapor relative to pressure of the gas to increase. When the pressure of this gas  Phlebotomy: Collecting and Processing Patient Blood Specimens 81 reaches ambient pressure, the collection process is completed TABLE 4-3 Examples of VACUETTE® for that tube. The specially designed, single-use needle holder SAFETY Cap Color Codes for Venous Blood is used to secure the needle. It is no longer acceptable to wash Collection and reuse this plastic needle holder device.7 DESCRIPTION ADDITIVE SAFETY CAP CAP Anticoagulants and Additives in Evacuated OF PLASTIC COLOR INNER Blood Tubes TUBES RING Evacuated blood collection tubes without anticoagulant are COLOR used to yield serum (or used as a discard tube) and other No Additive None White Black types of evacuated tubes may contain some type of antico- Tubes agulant or additive (Tables 4-2 and 4-3). The additives range Coagulation 3.2% Sodium Light blue Black Tubes citrate from those that promote faster clotting of the blood to those 3.8% Sodium Light blue Black that preserve or stabilize certain analytes (such as glucose) or citrate cells. The inclusion of additives at the proper concentration Serum Tubes Clot activator Red Black Clot activator Red or gold Yellow or with gel gold Heparin Tubes Lithium Green Black heparin TABLE 4-2 Examples of BD Stopper Lithium Green Yellow Colors for Venous Blood Collection* heparin with gel COLOR ADDITIVE Sodium Green Green Lavender K2EDTA (spray-coated plastic heparin tube) EDTA Tubes K2EDTA Lavender Black K3EDTA (liquid in glass tube) K2EDTA with Lavender or Yellow Pink K2EDTA (spray-coated plastic gel white tube) K3EDTA Lavender Black Light green/marbled green Sodium heparin, lithium Glycolytic NaFl/KO Gray Black heparin, ammonium heparin Inhibitor Tubes Light blue or clear Buffered sodium citrate, Trace Element Sodium Royal blue Black (Hemogard closure) CTAD Tubes heparin White† K2EDTA with gel ESR Tubes 3.2% Sodium Black standard — Red/light gray‡ or clear None (plastic) (not available in citrate stopper (Hemogard closure) U.S.) Red Silicone coated (glass) Clot activator, silicone coated EDTA, Ethylenediaminetetraacetate; ESR, erythrocyte sedimentation (plastic) rate; K2EDTA, dipotassium ethylenediaminetetraacetate; K3EDTA, Red/gray tripotassium ethylenediaminetetraacetate; KO, potassium oxalate; Gold/marbled red Clot activators and gel NaFl, sodium fluoride. Note: Tubes with a white inner cap ring refer to smaller draw Gray Sodium fluoride volumes of 2 ml. Black rings identify standard draw and yellow rings Yellow SPS: blood culture (Hemogard identify gel tube. closure) VACUETTE® Greiner Bio-One North America, Inc, Monroe, NC. Acid citrate dextrose: HLA studies (color stopper) Royal blue No additives for toxicology, trace metals (Hemogard) Orange/marbled yellow Thrombin Black Sodium citrate in evacuated tubes greatly enhances the accuracy and Tan Sodium heparin consistency of test results and facilitates faster turnaround times in the laboratory. CTAD, Citric acid, theophylline, adenosine, and dipyridamole; HLA, human leukocyte antigen; K2EDTA, dipotassium Anticoagulants ethylenediaminetetraacetate; K3EDTA, tripotassium ethylenediaminetetraacetate; SPS, sodium polyanatholsulfonate. There are several different types of inorganic additives (see inside Modified from BD Vacutainer venous blood collection tube guide, back cover), biochemical additives, or gel in blood collection Becton Dickinson. tubes. Some frequently used anticoagulants are tripotassium *See inside book cover for the comprehensive venous blood ethylenediaminetetraacetate (K3EDTA), dipotassium ethylene- collection tube guide, including additives, inversions of blood diaminetetraacetate (K2EDTA), sodium citrate, and heparin. collection, and laboratory use. † New tube for use in molecular diagnostic test methods. Each of the anticoagulant types prevents the coagulation of ‡ New red/light gray for use as a discard tube or secondary specimen whole blood. The proper proportion of anticoagulant to whole tube. blood is important to avoid the introduction of errors into 82 CHAPTER 4 test results. The specific type of anticoagulant needed for a pro- Heparin is the only anticoagulant that should be used cedure should be stated in the laboratory procedure manual. for the determination of pH, blood gases, electrolytes, and EDTA. The International Council for Standardization in ionized calcium. Heparin is used to coat “micro” (capillary Haematology (ICSH) and CLSI recommend the salts of the blood) collection tubes for use in certain hematology or clin- chelating (calcium-binding) agent EDTA as the anticoagulant ical chemistry procedures. of choice for blood cell counting and sizing, because EDTA Heparin is an inappropriate anticoagulant for many hema- produces less shrinkage of RBCs and less of an increase in tologic tests, including Wright-stained blood smears, because cell volume on standing. EDTA is spray-dried on the interior the smear will stain too blue. surface of evacuated plastic tubes. The proper ratio of EDTA to whole blood is important because some test results will Additives be altered if the ratio is incorrect. Excessive EDTA produces Thrombin. One type of additive is thrombin, an enzyme shrinkage of erythrocytes, thus affecting tests such as the that converts fibrinogen to fibrin. Thrombin tubes are often manually performed packed cell volume (microhematocrit). used for “stat” serum testing because of the short clotting time. K2EDTA and K3EDTA are found in evacuated tubes. The Sodium Fluoride. A dry additive and weak anticoagulant, mode of action of this anticoagulant is that it removes ion- sodium fluoride (NaFl) is used primarily for preservation of ized calcium (Ca2+) through the process of chelation. This blood glucose specimens to prevent glycolysis or destruction process forms an insoluble calcium salt that prevents blood of glucose (see Chapter 10). coagulation. Gel. The function of additive gel is to provide a physical EDTA is the most frequently used anticoagulant in hema- and chemical barrier between the serum or plasma and the tology for the complete blood cell count (CBC) or any of its cells. Their use offers significant benefits in collecting, pro- component tests: hemoglobin, packed cell volume, total leu- cessing, and storage of the specimen in the primary tube. kocyte count and leukocyte differential count, and platelet Separator gels are capable of providing barrier properties count. The modified Westergren erythrocyte sedimentation because of the way they respond to applied forces. After blood rate (ESR) method uses EDTA as the anticoagulant of choice. is drawn into the evacuated gel tube, and once centrifugation In addition, EDTA is used routinely for testing in blood begins, the g-force applied to the gel causes its viscosity to banking such as blood grouping, Rh typing, and antibody decrease, enabling it to move or flow. Materials with these screening. flow characteristics are often called thixotropic. Once centrif- K2EDTA with gel is used for testing plasma in molecular ugation ceases, the gel becomes an immobile barrier between diagnosis. K3EDTA may be used for viral marker testing. the supernatant and the cells. The composite nature of gels Sodium Citrate. Sodium citrate in concentrations of 3.2% gives these gel tubes a perpetual shelf life.6 and 3.8% solutions are available. Sodium citrate removes cal- Adverse Effects of Additives. The additives chosen for cium from the coagulation system by precipitating it into an specific determinations must not alter the blood components unusable form. Sodium citrate is effective as an anticoagulant or affect the laboratory tests to be done. The following are because of its mild calcium-chelating properties. Sodium citrate some adverse effects of using an improper additive or using is used as an anticoagulant for activated partial thromboplastin the wrong amount of additive: time (APTT) and prothrombin time (PT) testing and for the Interference with the assay. The additive may contain a classic Westergren ESR. The correct ratio of one part antico- substance that is the same, or reacts in the same way, agulant to nine parts whole blood in blood collection tubes is as the substance being measured, for example, use critical. An excess of anticoagulant can alter the expected dilu- of sodium oxalate as the anticoagulant for a sodium tion of blood and produce errors in the results. Because of the determination. dilution of anticoagulant to blood, sodium citrate is generally Removal of constituents. The additive may remove the unacceptable for most other hematology tests. constituent to be measured, for example, use of an oxa- Heparin. Heparin is used as an in vitro and in vivo antico- late anticoagulant for a calcium determination; oxalate agulant. Heparin acts as an antithrombin, or substance that removes calcium from the blood by forming an insolu- inactivates the blood-clotting factor thrombin and factor Xa. ble salt, calcium oxalate. This inactivation of thrombin is caused by the complexing Effect on enzyme action. The additive may affect enzyme of heparin with the antithrombin III molecule and catalyzing reactions, for example, use of NaFl as an anticoagu- the inhibition of thrombin. lant in an enzyme determination; NaFl destroys many Lithium heparin is the recommended form of heparin for enzymes. use in laboratory testing because it is least likely to interfere Alteration of cellular constituents. An additive may alter when performing tests for other ions. The in vitro formation cellular constituents, for example, use of an older anti- of fibrin in heparinized plasma opposes the anticoagulation coagulant additive, oxalate, in hematology. Oxalate action of heparin and can result in the subsequent formation distorts the cell morphology; RBCs become cren- of fibrin in the plasma. Several specimen-processing steps ated (shrunken), vacuoles appear in the granulocytes, are recommended to help ensure a good-quality heparinized and bizarre forms of lymphocytes and monocytes plasma sample to aid in minimizing the formation of latent appear rapidly when oxalate is used as the antico- fibrin. agulant. Another example is the use of heparin as an  Phlebotomy: Collecting and Processing Patient Blood Specimens 83 anticoagulant for blood to be used in the preparation the OSHA Bloodborne Pathogens Standard [29 CFR 1910.1030 of blood films that will be stained with Wright’s stain. (d)(2)(vii)(A)]. The standard prohibits the removal of a con- Unless the films are stained within 2 hours, heparin taminated needle from a medical device. Prohibition of needle gives a blue background with Wright’s stain. removal from any device is addressed in the 1991 and 2001 Incorrect amount of anticoagulant. If too little addi- standards, the OSHA compliance directive (CPL 2-2.69), and tive is used, partial clotting of whole blood will occur. in a 2002 letter of interpretation. Blood collected into the This interferes with cell counts. By comparison, if too syringe would then need to be transferred into a tube before much liquid anticoagulant is used, it dilutes the blood disposing of the contaminated syringe. In these situations, a sample and thus interferes with certain quantitative syringe with an engineered sharps injury prevention feature measurements. should be used whenever possible along with safe work prac- tices. Transfer of the blood from the syringe to the test tube Venipuncture Procedure must be done using a needleless blood transfer device. Safe Blood Collection: Equipment and Supplies As with any OSHA rule or regulation, noncompliance may Sterile needles are used. Various needle sizes are available. In result in the issuance of citations by an OSHA compliance addition to length, needles are classified by gauge size; the officer after the completion of on-site inspection. It is the higher the gauge number, the smaller the inner diameter, or responsibility of each facility to evaluate their work practices, bore. An increased emphasis on safety has led to new product implement appropriate engineering controls, and institute development by various companies. all other applicable elements of exposure control to achieve The standard needle for blood collection with a syringe compliance with current OSHA rules and regulations. The or evacuated blood collection tubes is a 21-gauge needle. OSHA SHIB provides a step-by-step Evaluation Toolbox for a Butterfly needles are being used more frequently as the acuity facility to follow (Box 4-1). of patients increases. The collecting needle is double pointed; the longer end is for insertion into the patient’s vein, and the shorter end pierces the rubber stopper of the discard and col- BOX 4-1 OSHA Safety and Health lection tubes. It is important to use an evacuated tube as a Information Bulletin: Evaluation Toolbox discard tube to remove the air from the tubing attached to the 1. Employers must first evaluate, select, and use appropri- butterfly needle. ate engineering controls (such as sharps with engineered The specially designed, single-use needle holder is used sharps injury protection), which includes single-use blood to secure the needle. It is not acceptable to wash and reuse a tube holders with sharps with engineered sharps injury pro- plastic needle holder device. For example, the BD Vacutainer tection (SESIP) attached. One Use Holder is a clear plastic needle holder prominently 2. The use of engineering and work practice controls provide marked with the words “Do Not Reuse” and “Single Use the highest degree of control in order to eliminate potential Only.” Once a venipuncture is completed, the entire needle injuries after performing blood draws. Disposing of blood and holder assembly is disposed of in a sharps container. The tube holders with contaminated needles attached after the needle should not be removed from the holder. No change in activation of the safety feature affords the greatest hazard control. venipuncture technique is required with a single-use holder. 3. In very rare situations, needle removal is acceptable. The Needlestick Safety and Prevention Act of 2000: If the employer can demonstrate that no feasible alterna- Requires health care employers to provide safety- tive to needle removal is available (such as the inability engineered sharps devices and needleless systems to to purchase single-use blood tube holders because of a employees to reduce the risk of occupational exposure supply shortage of these devices). to HIV, hepatitis C, and other bloodborne disease. If the removal is necessary for a specific medical or den- Expands the definition of engineering controls to include tal procedure. devices with engineered sharps injury protection. In these rare cases, the employer must ensure that the Requires that exposure control plans document con- contaminated needle is protected by a SESIP before sideration and implementation of safer medical devices disposal. In addition, the employer must ensure that a designed to eliminate or minimize occupational exposure. proper sharps disposal container is located in the im- mediate area of sharps use and is easily accessible to Plans must be reviewed and updated at least annually. employees. This information must be clearly detailed and Requires each health care facility to maintain a sharps documented in the employer’s Exposure Control Plan. injury log, with detailed information regarding percu- 4. If it is necessary to draw blood with a syringe, a syringe taneous injuries. with engineered sharps injury protection must be used, in Requires employers to solicit input from health care which the protected needle is removed using safe work workers when identifying and selecting sharps and doc- practices, and transfer of blood from the syringe to the tube ument process. must be done using a needleless blood transfer device. The U.S. Occupational Safety and Health Administration From Occupational Safety and Health Administration: Disposal of (OSHA) posted a Safety and Health Information Bulletin contaminated needles and blood tube holders used for phlebotomy. (SHIB) in 2003 to clarify the OSHA position on reusing tube Safety and Health Information Bulletin, October 2003. http://www. holders during blood collection procedures, a clarification of osha.gov/dts/shib/shib101503.html 84 CHAPTER 4 Preattached Blood Collection Needle and Holder. A pre- by the manufacturer. The stopper color denotes the type of attached needle holder provides additional protection from anticoagulant, additive, or the presence of a gel separator. tube holder–end needlestick injuries that virtually eliminates Increasingly, glass collection tubes are being replaced with a phlebotomist’s exposure to a contaminated needle. The risk safer plastic tubes. of reusing a needle holder is well recognized. The National Storage temperature for blood collection tubes should Phlebotomy Association (NPA) found that 99% of sampled be between 40 ° F and 77 ° F (4 ° C-25 ° C). If plastic tubes reusable holders were contaminated with blood, creating an reach higher temperatures, the tubes may lose their vacuum unnecessary risk of exposure to HIV, hepatitis C virus, hep- or implode. Evacuated tubes are intended for one-time use. atitis B virus, and other bloodborne pathogens for health When collecting multiple tubes of blood, a specified care workers and patients. (The complete statement along “order of draw” protocol should be followed to diminish the with more information about the NPA is available at www. possibility of cross-contamination between tubes caused by nationalphlebotomy.org.) the presence of different additives (Table 4-4). Errors in the The OSHA 2003 SHIB announced the practice of reuse order of draw can affect laboratory test results. of tube holders to protect health care workers from con- taminated back-end needles. Also in 2003, the Society for Syringe Technique Healthcare Epidemiology of America recommended the Disposable plastic syringes are used for special cases of venous adoption of single-use medical devices to prevent the spread blood collection. If a patient has particularly difficult veins, of microbes and the rise of new antibiotic-resistant infections. or if other special circumstances exist, the syringe technique A study of various types of safety-engineered devices to may be used. Some facilities recommend an order of draw prevent needlestick injuries concluded that automatic (pas- with a syringe that varies from the evacuated-tube protocol. sive) safety-engineered devices are more effective to reduce Currently, it is more common to use wing-tip (butterfly) blood needlestick injuries than semiautomatic and manually acti- collection sets for difficult patients or some pediatric patients. vated devices.7 Passive devices with automatic safety caused a needlestick injury at a rate of 0.06 per 100,000 uses. General Protocol 1. Phlebotomists should pleasantly introduce themselves to the Evacuated Blood Collection Tubes patient and clearly explain the procedure to be performed. Evacuated tubes are the most extensively used system for col- It is always a courtesy to speak a few words in a patient’s lecting venous blood samples. An evacuated blood collection native language if English is not his or her first language. system consists of a collection needle, a nonreusable needle Ethnic populations vary geographically, but many patients holder, and a tube containing enough vacuum to draw a spe- are now Spanish speaking. If a patient doesn’t understand cific amount of blood (Fig. 4-2). Evacuated tubes and micro- English and the phlebotomist is not fluent in the patient’s tainer tubes have various color-coded stoppers determined native language, an interpreter should be requested. POSITION 1 Preparation for venipuncture Container Holder A Double pointed needle.698 in. Min. ID.210 in. 17.7 mm. 5.3 mm..625 in. 15.9 mm. Notes 1. Needle to lock in place with POSITION 2 mating holder Collection of specimen 2. Stopper dimensions to allow for two positions as shown B FIGURE 4-2 Standard double-ended blood-collecting needle with holder using vacuum tube system. A, Preparation for venipuncture. B, Collection of specimen. (NCCLS H1-A4: Evacuated tubes and additives for blood specimen collection—fourth edition; approved standard, 1996.)  Phlebotomy: Collecting and Processing Patient Blood Specimens 85 TABLE 4-4 Order of Draw of Multiple Evacuated Tubes Collections* ORDER CLOSURE COLOR TYPE OF TUBE MIX BY INVERTING MIX BY INVERTING BD TUBES† GREINER TUBES‡ 1 Yellow Blood cultures: SPS—aerobic and 8-10× anaerobic 2 Light blue Citrate tube§ 3-4× 4× 3 Gold or red/gray BD Vacutainer SST gel separator tube 5× Red Serum tube (plastic) 5× 5-10× Red Serum tube (glass) None Orange BD Vacutainer RST 5-6× 4 Light green or green/gray PST gel separator tube with heparin 8-10× 5-10× Green Heparin 8-10× 5-10 5 Lavender EDTA 8-10× 5-10 6 White PPT separator tube K2EDTA with gel 8-10× 8-10× 7 Gray Fluoride (glucose) tube 8-10×× EDTA, Ethylenediaminetetraacetate; K2EDTA, dipotassium ethylenediaminetetraacetate; PPT, plasma preparation tube; PST, plasma serum tube; RST, rapid serum tube; SPS, sodium polyanatholsulfonate; SST, serum separator tube. *The order of draw has been revised to reflect the increased use of plastic evacuated collection tubes. Plastic serum tubes containing a clot activator may cause interference in coagulation testing. Some facilities may continue using glass serum tubes without a clot activator as a waste tube before collecting special coagulation assays. Reflects change in CLSI recommended order of draw (H3-A5, 23, 8.10.2). † Modified from Becton Dickinson, 2010. ‡ Modified from Greiner Bio-One § If a winged blood collection set for venipuncture is used, a discard tube should be drawn first. The blood flowing through the tubing into the discard tube displaces air in the tubing. This ensures a proper fill of blood into the evacuated tube with a proper blood anticoagulant ratio. The discard tube does not need to be completely filled. 2. Patient identification is the critical first step in blood verified to avoid any possible confusion when test results are collection. Patient misidentification errors are poten- sent to the ordering physician. tially associated with the worst clinical outcomes be- 3. The patient should be asked if he or she is taking any cause of the possibility of misdiagnosis and mishandled medications, including over-the-counter medications therapy.1 such as aspirin. It is particularly important that patients It is necessary to have the patient state and speak his or her inform personnel if they are taking an anticoagulant such name. If a patient cannot provide this information, he or she as warfarin (Coumadin). When therapeutic drug levels must provide some form of identification or must be identi- are being determined, it is important to ask when the last fied by a family member or caregiver. Check the identification dose of a medication was consumed. band that is physically attached to the patient. Wristbands 4. Test requisitions should be checked and the appropriate with unique bar-coded patient identifiers have great poten- evacuate tubes assembled. All specimens should be prop- tial for reducing patient misidentification. Unfortunately, erly labeled immediately after the specimen is drawn. wristband errors do occur. A study conducted the College of Prelabeling is unacceptable. American Pathologists (CAP) identified six major types of 5. The patient’s name, unique identification number, room wristband errors, as follows: number or clinic, and date and time of collection are usu- Absent wristband ally found on the label. In some cases, labels must include Wrong wristband the time of collection of the specimen and the type of More than one wristband with different information specimen. A properly completed request form should ac- Partially missing information on the wristband company all specimens sent to the laboratory. Erroneous information on the wristband note: Capillary blood collection is performed with a ster- Illegible information on the wristband ile, disposable lancet. These lancets should be properly dis- When the patient is unable to give his or her name, or carded in a puncture-proof container after a single use. when identification is attached to the bed or is missing, nurs- ing personnel should be asked to identify the patient physi- Labels cally. Any variations in protocol should be noted on the test Quality assessment policies are implemented in the clinical requisition. A CAP recommendation is that phlebotomists laboratory to protect the patient from any mistakes resulting should refuse to collect blood from a patient when a wrist- from errors caused by improperly handled specimen, begin- band error is detected. ning with the collection of that specimen. Laboratory quality The current requirement for two patient identifiers usu- assessment and accreditation require that specimens be prop- ally includes the patient stating his or her full name and the erly labeled at the time of collection. All specimen containers date of birth. The name of the patient’s physician should be must be labeled by the person doing the collection to ensure 86 CHAPTER 4 the specimen is actually collected from the patient whose phases of laboratory processing and testing. Labeling errors identification is on the label. Additional labeling require- can most often be divided into three categories: unlabeled, ments such as a separate blood banking wristband and iden- mislabeled, and mismatched specimen to requisition. All tification of the phlebotomist are enforced for routine blood efforts should result in a decrease in labeling errors. The bank testing such as red cell grouping, Rh typing, and anti- impact of these errors is significant in causing negative body screening. patient outcomes. An unlabeled container or one labeled improperly should not be accepted by the laboratory. Specimens are considered improperly labeled when there is incomplete or VENOUS BLOOD COLLECTION (PHLEBOTOMY) no patient identification on the tube or container holding the specimen. Many specimen containers are transported in Supplies and Equipment leakproof plastic bags. It is unacceptable practice for only The following is a list of supplies and equipment that will be the plastic bags to be labeled; the container actually holding needed in venipuncture (Student Procedure Worksheet 4-1): the specimen must be labeled as well. If the identification is Test requisition illegible, the specimen is unacceptable. A specimen is also Tourniquet and disposable gloves unacceptable if the specimen container identification does Sterile disposable needles and needle holder not match exactly the identification on the request form for Various evacuated blood tubes that specimen. Alcohol (70%) and gauze square or alcohol wipes Any special equipment Bar Codes Adhesive plastic strips The AUTO12 system addresses location and orientation of bar code identifiers as well as bar code symbols. The U.S. Special Blood Collection: Blood Cultures Centers for Disease Control and Prevention identified use A serious avoidable error is blood culture contamination. of bar codes as a best practice for reducing specimen iden- Contamination can cause false-positive results, diagnostic tification errors. In many laboratories, labels are computer errors, and increased cost and length of hospitalization. generated, which helps ensure that the proper identification The American Society for Microbiology (ASM) benchmark information is included for each patient. Bar-coded labels for contaminated cultures is no greater than 3%. The ASM facilitate this process. One automated computer system, the recommends that two to four sets of blood cultures be col- BD.id Patient Identification System, eliminates mislabeling lected. If only one specimen is positive, the physician can because the system reads the patient’s bar-coded wristband. conclude it is a contaminated culture. Reduction in con- The software indicates the tests, appropriate tubes, and quan- tamination rate can be achieved if personnel are properly tity of tubes required for the patient, then generates bar- trained and managed. Some institutions have blood culture coded laboratory labels for tube identification at the patient’s collection teams. bedside. Each laboratory has a specific protocol for the han- The ASM target rate or lower can be achieved by following dling of mislabeled or “unacceptable” specimens. a strict protocol for blood collection, banning repalpation of Clinical laboratory professionals developed the CLSI doc- the venipuncture site, and avoiding drawing blood from an ument AUTO12-A, Specimen Labels: Content and Location, indwelling IV line. To prevent contamination, blood-drawing Fonts, and Label Orientation. The deadline for labora- site preparation is the first step in the protocol. tory compliance, April 29, 2014, will not affect a laborato- The CLSI has discontinued the traditional technique of ry’s accreditation, but accrediting bodies such as The Joint preparing the venipuncture site with a circular motion from Commission (TJC) and CAP are expected to require medi- its blood culture guideline because it is not an evidence-based cal laboratories to comply with this bar code specimen label practice in infection control. An antiseptic such as alco- standard. Laboratories already complying with this standard hol, tincture of iodine, chlorhexidine, or povidone-iodine report that compliance has significantly improved specimen (Betadine) is left on the skin for 30 seconds of contact time tracking. The adoption and use of the standardized bar code to destroy bacteria. After preparation, the site must not be label require a small investment, but then becomes “the gift repalpated. If the phlebotomist must repalpate, the skin must that goes on giving.”8 This investment provides a return in be prepared as it was originally. A practice allowed by ASM cost savings from a reduction in errors, a factor that is par- guidelines is to apply antiseptic to the gloved finger before ticularly important when laboratory budgets are shrink- repalpating. The venipuncture should enter the vein directly, ing. Mislabeling error rates in the United States have been not through an inserted IV line. (See Chapter 15 for further reported to range from 0.1% to 5%.9 discussion of blood culture collection and related topics.) In the 2013 TJC Laboratory Services National Patient Safety Goals,10 the first goal is improving the accuracy in Special Site-Selection Situations patient identification. These goals require two identifiers on Five specific situations may result in a difficult venipuncture each patient specimen, with the directive that all specimens or may be sources of preanalytical error: IV lines, edema, must be labeled in the presence of the patient. AUTO12 cov- scarring or burn patients, dialysis patients, and mastectomy ers specimen labeling from the time of collection through all patients.  Phlebotomy: Collecting and Processing Patient Blood Specimens 87 Intravenous Lines 3. Anemia. Iatrogenic anemia is also known as nosocomial A limb with an IV line running should not be used for anemia, physician-induced anemia, or anemia resulting venipuncture because of contamination to the specimen. from blood loss for testing. This can be a particular problem The patient’s other arm or an alternate site should be with pediatric patients. selected. 4. Neurologic complications. Postphlebotomy patients can exhibit some neurologic complications, including seizure Edema or pain. Edema is the abnormal accumulation of fluid in the intracel- 5. Cardiovascular complications. Cardiovascular compli- lular spaces of the tissue. cations include orthostatic hypotension, syncope, shock, and cardiac arrest. Scarring or Burn Patients 6. Dermatologic complications. The most common der- Veins are very difficult to palpate in areas with extensive scar- matologic consequence of phlebotomy is an allergic reac- ring or burns. Alternate sites or capillary blood collection tion to iodine in the case of blood donors. should be used. CAPILLARY OR PERIPHERAL BLOOD Dialysis Patients Blood should never be drawn from a vein in an arm with a COLLECTION BY SKIN PUNCTURE cannula (temporary dialysis access device) or fistula (per- Capillary blood can be used for a variety of laboratory assays. manent surgical fusion of vein and artery). A trained staff Capillary blood is often used for point-of-care tests (POCTs). member can draw blood from a cannula. The preferred veni- A common POCT is bedside testing for glucose using one puncture site is a hand vein or a vein away from the fistula on of several available reading devices and the accompany- the underside of the arm. ing reagent strips, as done at home by diabetic patients (see POCT discussion). Mastectomy Patients If a mastectomy patient has had lymph nodes adjacent to the Blood Spot Collection for Neonatal Screening breast removed, venipuncture should not be performed on Programs the same side as the mastectomy. Most states have passed laws requiring that newborns be screened for certain diseases that can result in serious Phlebotomy Problems abnormalities, including mental retardation, if they are not Occasionally, a venipuncture is unsuccessful. Do not attempt diagnosed and treated early. These diseases include phenyl- to perform the venipuncture more than twice. If two attempts ketonuria (PKU), galactosemia, hypothyroidism, and hemo- are unsuccessful, notify the phlebotomy supervisor. Problems globinopathies. CLSI11 has set standards for filter paper encountered in phlebotomy can include the following: collection, or blood spot collection, of blood for these screen- 1. Refusal by the patient to have blood drawn ing programs. Blood should be collected 1 to 3 days after 2. Difficulty obtaining a specimen because the bore of birth, before the infant is discharged from the hospital, and the needle is against the wall of the vein or is going at least 24 hours after birth and after ingestion of food for through the vein a valid PKU test. There is an increased chance of missing a 3. Movement of the vein positive test result when an infant is tested for PKU before 4. Sudden movement by the patient or phlebotomist that 24 hours of age. When infants are discharged early, however, causes the needle to come out of the arm prematurely many physicians prefer to take a sample early rather than risk 5. Needle angles that result in missing the vein no sample at all. 6. Problems with collapse of a vein In most neonatal screening programs the specimen is col- 7. Hematoma that results from the needle bevel being lected on filter paper and then sent to the approved testing halfway into the vein with the other half still in the laboratory for analysis. Special collection cards with a filter tissue paper portion are supplied by the testing laboratory; these 8. Inadequate amount of blood in an evacuated tube are kept in the hospital nursery or central laboratory. There 9. Fainting or illness subsequent to venipuncture is an information section on these cards, and all requested information must be provided and should be treated as any Phlebotomy Complications other request form. The filter paper section of the card con- Patients can experience complications resulting from a phle- tains circles designed to identify the portion of the paper botomy procedure. These complications can be divided into onto which the specimen should be placed, where the filter the following six major categories: paper will properly absorb the amount of blood necessary 1. Vascular complications. Bleeding from the site of the ve- for the test. nipuncture and hematoma formation are the most com- Collection is usually done by heel puncture following the mon vascular complications. accepted procedure for the institution. When a drop of blood 2. Infections. The second most common complication of is present, the circle on the filter paper is touched against the venipuncture is infection. drop until the circle is completely filled. A sufficiently large 88 CHAPTER 4 drop should be formed so that the process of filling the circle strip pad and, according to the specific procedure, read in can be done in only one step. The filter paper is allowed to the meter. The instrument provides an accurate and stan- air-dry and then is transported to the testing laboratory in dardized reading when used according to the manufacturer’s a plastic transport bag or other acceptable container. The directions. The reagent strips must be handled with care and procedure established by the testing laboratory should be fol- used within their proper shelf life. The strips are specific only lowed for the collection step. for glucose. The meters are packaged in convenient carry- ing cases and are small enough to be placed in a pocket or Capillary Blood for Testing at the Bedside briefcase. (Point-of-Care Testing) Capillary blood samples for glucose testing and for other CAPILLARY BLOOD COLLECTION assays are used frequently in many health care facilities for bedside testing, or POCT. Quantitative determinations for Supplies and Equipment glucose are made available within 1 or 2 minutes, depending The following is a list of supplies and equipment that will on the system employed. CLSI12 has set guidelines for these be needed in capillary blood collection (Student Procedure tests because they are performed in acute care and long-term Worksheet 4-2): care facilities. Alcohol (70%) and gauze squares or alcohol wipes Many diabetic outpatients also perform POCT for glu- Disposable gloves and sterile small gauze squares cose at home by using their own blood and one of several Sterile disposable blood lancets glucose-measuring devices. It is important for diabetic Equipment specific to the test ordered (such as glass patients, especially those with insulin-dependent diabetes slides for blood smears, micropipette and diluent for mellitus, to monitor their own blood glucose levels several CBCs, and microhematocrit tubes) times a day and to be able to adjust their dosage of insulin accordingly to maintain good glucose control. Special Capillary Blood Collection For the diabetic inpatient, POCT is also a valuable tool for Unopette diabetes management. The blood glucose level is often unsta- The BD Unopette collection system is no longer available. An ble in these patients, a situation that may necessitate frequent alternative equivalent product is manufactured by Bioanalytic adjustments of insulin dosage. POCT provides results that are GmbH. These U.S. Food and Drug Administration (FDA)– immediate, so dosages can be adjusted more quickly. Ordering approved products have been on the European market since and collecting venous blood specimens for glucose tests done 1978 (www.bioanalytic.de). by a central laboratory, with the necessary frequency and A product insert describes the collection and processing rapidity of reporting required, are often impractical, making procedure used in special capillary blood collection. POCT much more useful. Good quality control programs must be used to ascertain the reliability of the POCT results. Capillary Blood for Slides Whole-blood samples should be collected by puncture from To collect capillary blood for slides, a finger or heel puncture the heel (for infants only), finger, or flushed heparinized line, is made, and after the first drop is wiped away, the glass slide using policies for Standard Precautions. Arterial or venous is touched to the second drop formed. The slide is placed blood should not be used unless the directions from the man- on a flat surface and a spreader slide used to prepare the ufacturer of the POCT device specify the appropriateness of smear (see Chapter 11). The slide is allowed to air-dry, is these alternative blood specimens. The POCT instrument properly labeled, and then transported to the laboratory for should be calibrated and the test performed according to the examination. manufacturer’s directions. Results should be recorded perma- nently in the patient’s medical record in a manner that dis- Collecting Microspecimens tinguishes between bedside test results and central laboratory At times, only small amounts of capillary blood can be test results. collected (Box 4-2), and many laboratory determinations It is critical to understand and consider the specific lim- have been devised for testing small amounts of sample. In itations of each POCT detection system, as described by the general, the same procedure is followed as for any other manufacturer, so reliable results are obtained. A quality assess- drawing of capillary blood. For chemistry procedures, ment program is mandatory to ensure reliable performance blood can be collected in a capillary tube or microcontain- of these procedures. The use of POCT, whether bedside test- ers (Figs. 4-3 and 4-4) by touching the tip of the tube to ing or self-testing for glucose, is intended for management of a large drop of blood while the tube is held in a slightly diabetic patients, not for initial diagnosis. POCT is not used downward position. The blood enters the collection unit to replace the standard laboratory tests for glucose, but only by capillary action. Several tubes can be filled from a single as a supplement. skin puncture if needed. Tubes are capped and brought to Several commercial instruments are available, and with the laboratory for testing. Careful centrifugation technique each product, a meter provides quantitative determination must be used if serum is needed. Microcontainers are avail- of glucose present when used with an accompanying reagent able with various additives, including serum separator gels strip. A drop of capillary blood is touched to the reagent (Table 4-5).  Phlebotomy: Collecting and Processing Patient Blood Specimens 89 BOX 4-2 Order of Draw for Capillary TABLE 4-5 Order of Draw for BD Specimens Microtainer Tubes with BD Microgard Closure 1. Blood gases 2. Ethylenediaminetetraacetate tubes CLOSURE ADDITIVE MIX BY 3. Other additive minicontainers COLOR INVERTING 4. Serum 1. Lavender K3EDTA 10× Order of draw for capillary blood collection is different from blood 2. Green Lithium heparin 10× specimens drawn by venipuncture. 3. Mint green Lithium heparin and gel 10× From Clinical and Laboratory Standards Institute: Procedures and for plasma separation devices for the collection of diagnostic blood specimen by skin 4. Gray NaFl puncture: approved standard, ed 6, Wayne, Pa, 2008, H4-A6.* Na2EDTA 10× note: If multiple specimens are collected by heelstick or fingerstick 5. Gold Clot activator and gel for 5× puncture (capillary blood collection), anticoagulant tubes must be serum separation collected first to avoid the formation of tiny clots resulting from 6. Red No additive 0× prolonged collection time. Blood gases should be collected first, if the phlebotomy team is responsible for collection of these K3EDTA, Tripotassium ethylenediaminetetraacetate; Na2EDTA, specimens. disodium ethylenediaminetetraacetate; NaFl, sodium fluoride. *BD Diagnostics: Lab Notes 20(1):2, 2009, Becton Dickinson. note: Hold tube upright, gently invert 180 degrees and back, and repeat movement as recommended. If not mixed properly, tubes with anticoagulants will clot and specimen will often need to be recollected. Modified From BD Diagnostics: LabNotes 20(1):7, 2009, Becton Dickinson. FIGURE 4-3 Microtainer tube system. (From Warekois RS, Robinson R: Phlebotomy: worktext and procedures manual, ed 3, St Louis, 2012, Elsevier/Saunders.) FIGURE 4-5 OneTouch lancing device. (Courtesy LifeScan, Milpitas, Calif.) A laser device emits a pulse of light energy that lasts a fraction of a second. The laser concentrates on a very small portion of skin, literally vaporizing the tissue about 1 to 2 mm to the capillary bed. The device can draw a 100- μL blood sample, a sufficient amount for certain tests. FIGURE 4-4 Microvette® capillary blood collection system. The laser process is less painful and heals faster than when (Courtesy Sarstedt Inc, Newton, NC.) blood is drawn with traditional lancets. The patient feels a sensation similar to heat rather than the prick of a sharp Laser Equipment object. Laser technology is the first radical change in phlebotomy in more than 100 years. Revolutionary devices received approval from the FDA in 1997. The Lasette (Cell Robotics, SPECIMENS: GENERAL PREPARATION Albuquerque, NM) and the Laser Lancet (Transmedica Accurate chemical analysis of biological fluids depends on International, Little Rock, Arkansas) can draw blood without proper collection, preservation, and preparation of the sam- the use of sharp objects (Fig. 4-5). ple, in addition to the technique and method of analysis used. 90 CHAPTER 4 The most quantitatively perfect determination is of no use When stoppers must be removed from the tubes to obtain if the specimen is not properly handled in the initial steps of plasma or serum, the stopper must be removed carefully and the procedure. not popped off, because this could cause infection by inha- lation or by contact of the infectious aerosol with mucous Processing Blood Specimens membranes. Stoppers should be twisted gently while being Blood specimens must be properly handled after collection. covered with protective gauze to minimize the risk from aero- Blood samples should be analyzed as promptly as possible. solization. This processing step can be done using a protective Institutional protocol should be followed for conditions of plastic shield to prevent direct splashes. storage (such as room temperature, refrigerated, or frozen), It is generally best to test specimens as quickly as possi- depending on the analyte to be measured. In general, speci- ble. Specimens should be processed to the point where they mens should be analyzed within 24 hours of collection. It is can be properly stored so that the constituents to be mea- important that the proper evacuated tube be used, especially sured will not be altered. Specimens collected at collection if a specimen is being analyzed for glucose, which requires a stations away from the testing laboratory need to guarantee preservative. that delivery will be made in less than 2 hours from collec- If no anticoagulant is used, the blood will clot, and serum tion and that specimens have been stored properly, includ- is obtained. The serum is then removed from the clot by cen- ing refrigeration or freezing if necessary. Testing laboratories trifugation. To prevent excessive handling of biological fluids, provide specific instructions on the collection, processing, many laboratory instrumentation systems can now use the and delivery requirements for all assays that they perform. serum directly from the centrifuged tube, without another If the centrifuged serum or plasma must be removed into separation step and without removing the stopper. a separate tube or vial, pipette the serum or plasma by using It is important to remove the plasma or serum from the mechanical suction and a disposable pipette; use a protective remaining blood cells, or clot, as soon as possible. Because plastic shield to prevent direct splashes. All serum and plasma biological specimens are being handled, the need for certain tubes, as well as the original blood tubes, should be discarded safety precautions is stressed. The Standard Precautions policy properly in biohazard containers when they are no longer should be used because all blood specimens should be consid- needed for the determination. ered infectious and must be handled with gloves. The outside of the tubes may be bloody, and initial laboratory handling of Centrifuging the Specimens all specimens necessitates direct contact with the tubes. After clotting has taken place, the tube is centrifuged with its To separate the serum and plasma from blood cells or cap on (Fig. 4-6). It is important to use Standard Precautions, a blood clot, tubes must have stoppers for centrifugation. which require all persons handling specimens to wear gloves. Serum Serum Serum Clotted cells Gel Cells (clot) Gel Clotted cells A B C FIGURE 4-6 A, Gold SST tube centrifugation. Note position of the gel on the bottom. B, Gold SST tube after centrifugation. Note that the gel now separates the serum from the clotted cells. C, Centrifuged red-topped “clot” tube with no gel or clotting additive. (Modified from Bonewit-West K: Clinical procedures for medical assistants, ed 6, Philadelphia, 2004, Saunders.)  Phlebotomy: Collecting and Processing Patient Blood Specimens 91 When necessary, stoppers must be carefully removed from an increase in bile pigments (i.e., bilirubin). Excessive intra- blood collection tubes to prevent aerosolization of the spec- vascular destruction of RBCs, obstruction of the bile duct, or imen. Centrifuges must be covered and placed in a shielded impairment of the liver leads to an accumulation of bile pig- area. When serum or plasma samples must be removed from ments in the blood, and the skin becomes yellow. Those per- the blood cells or clot, mechanical suction is used for pipet- forming clinical laboratory determinations should note any ting, and all specimen tubes and supplies must be discarded abnormal appearance of serum or plasma and record it on properly in biohazard containers. the report form. The abnormal color of the serum can inter- The use of automated analyzers often allows the use of the fere with photometric measurements. primary collection tube for the analysis itself. In these cases, the primary blood tube is centrifuged with its cap on, and the Lipemic Specimens serum is aspirated directly into the analyzer. Lipemic plasma or serum takes on a milky white color. The presence of lipid, or fats, in serum or plasma can cause this Unacceptable Specimens abnormal appearance. Often, the lipemia results from collect- Various conditions render a blood specimen unsuitable for ing the blood from the patient too soon after a meal. Use of testing. Clotted specimens are not suitable for cell counts a lipemic serum specimen does not interfere with some lab- because the cells are trapped in the clot and are therefore not oratory determinations, but others may be affected (such as counted. A cell count on a clotted sample will be falsely low. trigly