Week 8 Handout PDF - Phlebotomy

MA - 156 - Phlebotomy WEEK 8 Capillary collections, Point-of-care testing, and pediatrics 01 CAPILLARY COLLECTION Capillary collection, also called dermal puncture or skin puncture, is the usual collection procedure for infants. In adults, it is an alternative collection procedure when minute amount...

MA - 156 - Phlebotomy WEEK 8 Capillary collections, Point-of-care testing, and pediatrics 01 CAPILLARY COLLECTION Capillary collection, also called dermal puncture or skin puncture, is the usual collection procedure for infants. In adults, it is an alternative collection procedure when minute amounts of blood are needed for testing, or for patients for whom venipuncture is inadvisable or impossible. In addition, it is typically used when collecting blood from infants and point-of-care testing. The depth of puncture must be carefully controlled to produce adequate flow while avoiding contact with underlying bone. Skin puncture devices deliver a precise incision, and microsample containers, sized to fit the desired sample, collect the blood from the puncture site. Reasons for Performing Capillary Collection Although venipuncture is the most common way to obtain a blood sample, at times it is impossible or inadvisable to do so. In these situations, capillary collection (also called skin puncture or dermal puncture) offers a valuable alternative. Capillary collection is the preferred method for obtaining blood from newborns and infants for neonatal bilirubin, newborn screening, and point-of-care testing. Capillary collection is also used for ancillary blood glucose testing. A requisition form generally does not state that a capillary collection should be performed, and it is up to the phlebotomist to choose the best collection method for the tests ordered. For this reason, you must be familiar with the advantages, limitations, and appropriate uses of capillary collection. Knowing how and when to perform a capillary collection is a vital skill for a phlebotomist. Capillary collection is preferred in several situations and for several types of patients. Adult patients undergoing frequent glucose monitoring are excellent candidates for capillary collection, because the test requires only a small amount of blood, which must be taken frequently. Access to venipuncture sites may be difficult with obese patients, whose veins are often hard to find, and with geriatric patients, who often have small or fragile veins that can make obtaining venous blood difficult. Venipuncture may be contraindicated for patients with burns or scars over venipuncture sites or for those at risk for venous thrombosis (caused when clots form within the veins), because venipuncture increases the risk of venous thrombosis. Other patients may be at risk for serious complications associated with deep venipuncture, including iatrogenic anemia, hemorrhage, infection, organ or tissue damage, arteriospasm, or cardiac arrest. Iatrogenic anemia is anemia caused by excessive blood draws. Capillary collection is usually the preferred method of collection for newborns, infants, and children younger than 2 years. Young children’s smaller veins and lower blood volume make venipuncture both difficult and potentially dangerous. Reducing blood volume through venipuncture is a concern for newborns and infants. It may lead to anemia and even cardiac arrest and death. In addition to serving as a substitute for venipuncture, capillary blood gas (CBG) determination can be used as an alternative to arterial puncture for arterial blood gas (ABG) determination in infants. However, some tests cannot be performed on blood from a capillary collection. These include blood cultures, erythrocyte sedimentation rate (ESR), coagulation tests, and tests requiring larger volumes of plasma or serum. Capillary collection may not be appropriate for severely dehydrated patients, because test results may not be accurate. (This may also be a concern with venipuncture for such patients.) Capillary collection should not be used at sites that are swollen or where circulation or lymphatic drainage is compromised (such as a limb on the same side as a mastectomy). Differences Between Venous and Capillary Blood A capillary puncture collects blood from capillaries. Because capillaries are the bridges between arteries and veins, blood collected by capillary puncture is a mixture of venous blood and arterial blood. The arterial proportion in the sample is increased when the collection site is warmed, as may be done to help increase blood flow before collection. Small amounts of tissue fluid from the puncture site may also be in the sample, especially in the first drop. The levels of many substances are the same in both capillary and venous blood, but this is not the case for all substances, as indicated in the table below. For instance, the normal potassium reading obtained by capillary collection is lower than that in a plasma sample obtained by venipuncture, but higher than that in a serum sample obtained by venipuncture. Because of these differences, results obtained by the two techniques cannot be compared. For this reason as well, it is important to record that the sample was obtained by capillary collection. Equipment for Capillary Collection Capillary collection equipment allows the phlebotomist to puncture the skin safely and collect the sample quickly and efficiently, with a minimum of discomfort for the patient. Skin Puncture Devices Skin puncture devices in the modern healthcare environment are designed with a retractable blade per Occupational Safety and Health Administration (OSHA) safety regulations. Some devices are contact activated, whereas others require the phlebotomist to depress a trigger to release the blade. Automatic puncture devices deliver a swift puncture to a predetermined depth, which can be a significant advantage at sites where the bone is close to the skin (see “Site Selection”). The dimensions of the puncture are controlled by the width and depth of the point. Some automatic puncture devices have a platform that is positioned over the puncture site and color coded for different depths. (The automatic devices designed for home glucose testing make a cut that is too small for multiple tests or for filling several microsample containers and are not used in clinical practice.) Safety features include retractable blades and locks that keep a blade from being used a second time and prevent accidental sticks to the phlebotomist. There are heel incision devices specifically for newborns and premature babies. The method of puncture by the blade is different from a typical puncture device. The puncture is a sweeping arc instead of a perpendicular puncture. This is a smoother cut that minimizes bruising and reduces contact with nerve endings, therefore minimizing pain to the infant. Various sizes are available based on the age, birth status, and size of the infant. The Lasette laser lancing device is unique in that it uses a laser, rather than a sharp instrument, to pierce the skin, which causes less pain and bruising at the sample site. Cross-contamination between patients is avoided by disposing of the single-use lens cover between uses. The device is approved for patients 5 years and older. Microsample Containers Microsample containers (also called bullets) come in a range of sizes that accommodate various volumes of blood. The fill volumes of the microsample containers range from 250 μL up to 750 μL. Microcollection tubes are made of plastic and contain a variety of anticoagulants and additives. The tubes are color coded by additive to match the coding of evacuated containers. Microcollection tubes are used for all types of dermal puncture collections and are the most common type of collection containers used for dermal puncture samples. They are also available with a plastic capillary tube that is fitted inside the container to aid in the collection of the sample. Capillary tubes are available in plastic and come in a range of sizes. These tubes are used primarily for the collection of samples for CBG (capillary blood gases) determinations. Caraway or Natelson pipets are narrow plastic tubes with capacities up to about 470 μL. Capillary tubes are available either plain with a blue band, or heparin coated, with a red, yellow, or green band (colors may vary with the manufacturer). Once the sample is in the tube, one or both ends are sealed. Sealing used to be done by pushing the ends into soft clay. New, safer sealing methods are recommended that instead fit the ends with small plastic caps. Both ends must be sealed for a CBG determination. In the laboratory, the sample may be centrifuged to separate cells from plasma or serum. The sample can be removed with a syringe. Microhematocrit tubes are small plastic tubes, with a volume up to 75 μL. These tubes are used infrequently and have been largely replaced by microcollection containers. However, when a spun hematocrit is requested, a plastic capillary tube can be used. Finally, capillary collection is also used in neonatal screening for a variety of inherited diseases. In this situation, no collection container is used. Instead, drops of blood are applied directly to specially prepared filter paper. Additional Supplies As in venipuncture, alcohol pads are used to prepare the site, and gauze pads are used to help stop the bleeding. A sharps disposal container is needed for the lancet. Warming devices increase arterial circulation by sevenfold. Simple towels or washcloths may be soaked in warm water and applied to the site. Be sure that the site is completely dry before puncture, however, as residual water will cause hemolysis and dilution of the specimen. Commercial warming packs are also available. The pack is first wrapped in a dry towel and then activated by squeezing. Such “heel warmers” are often used when blood must be collected from infants. The temperature of the device should not exceed 42° C, and it should be applied for 3 to 5 minutes. Glass slides are used to prepare blood smears for microscopic examination of blood cells. Site Selection General Considerations Capillary collection should be performed on warm, healthy skin that is free of scars, cuts, bruises, and rashes. The site must be easily accessible and have good capillary flow near the skin surface, but there must be enough clearance above the underlying bone to prevent the lancet from accidentally contacting it. This applies to both the finger and the heel. Bone puncture can lead to osteochondritis, a painful inflammation of the bone or cartilage, or osteomyelitis, a potentially serious, sometimes fatal, bone infection. You should also avoid skin that has been damaged or compromised in any way. This also applies to both the finger and the heel. Specific areas to avoid include skin that is callused, scarred, burned, infected, bruised, edematous, or bluish. Also avoid previous puncture sites as well as sites where circulation or lymphatic drainage is compromised. This is because tissue fluid accumulates in both previously punctured sites or bruised sites. The tissue fluid contaminates the sample therefore causes erroneous test results. When performing a capillary puncture for a mastectomy patient, you must perform the puncture on the side opposite the mastectomy, unless the physician has given permission to perform it on the same side. Puncture Depth and Width The depth of the puncture depends on the site and the patient. To minimize the risk of inflammation and infection, the lancet should never penetrate more than 3.0 mm. For a heel puncture, the maximum depth is 2.0 mm, because the calcaneus, or heel bone, can lie very close to the surface. For premature babies, the recommended depth is 0.65 to 0.85 mm. Puncture width should not exceed 2.5 mm for a heel stick in an infant. The heel incision device for premature babies has a puncture width of 1.75 mm. At the right site, this achieves adequate blood flow but remains well above the bone. Puncture width is actually more important than depth in determining blood flow, because capillary beds may lie close to the skin, especially for newborns. A wider cut severs more capillaries and produces greater flow without affecting nerve endings and bone tissue. Capillary Collection Sites for Adults and Older Children For adults and for children older than 1 year, dermal punctures are almost always performed on the fingertips of the nondominant hand. The best sites are the palmar surface of the distal segments of the third (middle) and fourth (ring) fingers. The thumb is likely to be callused, and the index finger’s extra nerve endings make punctures more painful. The little finger (pinky) has too little tissue for safe puncture. If the fingers cannot be used, the big toe may be an option— check the policy at your workplace. Earlobes are never used for dermal puncture. The puncture should be made near the fleshy center of the chosen finger. Avoid the edge of the finger, as the underlying bone is too close to the surface. The puncture should be made perpendicular to (across) the ridges of the fingerprint, which lessens the flow of blood into the grooves. Capillary Collection Sites for Infants For children younger than 1 year, there is too little tissue available in any of the fingers. According to CLSI, fingersticks should never be performed on children under the age of 1 year. For this reason, dermal puncture is performed in the heel. Only the medial and lateral borders of the plantar (bottom) surface can be used. The center of the plantar surface is too close to the calcaneus, as is the posterior (back) surface. The arch is too close to nerves and tendons. For older infants, the big toe may be used if the heel is unacceptable. Be aware that the heel may be callused on young children who have begun to walk. 02 CAPILLARY PROCEDURE Capillary Collection In addition to these specific steps, you should always greet the patient, identify the patient, and obtain consent, as you would for a routine venipuncture. Assemble your equipment. - Use the patient’s age and the tests ordered to determine which type of collection tube you will need, what type of skin puncture device to use, and whether to use a warming device. Select and clean the site. - Warm the area first, if necessary. If the site feels cold, it should be warmed for at least 3 minutes at a temperature no greater than 42°C. If a wet washcloth is used, be sure to remove any residual water, as residual water will cause hemolysis and dilution of the specimen. Use 70% isopropyl alcohol to clean the site. Allow the site to dry completely. In addition to causing stinging, contamination, and hemolysis, residual alcohol interferes with the formation of rounded drops of blood on the skin surface. (Use of povidone–iodine is not recommended for dermal punctures, because it may elevate test results for bilirubin, uric acid, phosphorus, and potassium. Remember the acronym BURPP to help you learn this group of tests.) Massaging the finger proximal to the puncture site (closer to the palm) can help increase blood flow. To avoid hemolysis, massage gently, and do not squeeze. Position and hold the area. - Hold the finger or heel firmly. This prevents it from moving during the puncture and reassures the patient. Grasp the patient’s finger with its palmar surface up, holding it between your thumb and index finger. To hold the patient’s heel, place your thumb in the arch, wrap your hand over the top of the foot, and place your index finger behind the heel. Make the puncture, and dispose of the blade properly.- Align the device so the cut is made across the fingerprint ridges or heel lines. This allows the blood to flow out and make a rounded drop, rather than run into the grooves. Puncture the skin slightly to either side of the center of the finger. Do not lift the device immediately after the puncture is complete. Count to two before lifting the device to ensure that the blade has made the puncture to the full depth and width, then fully retracted. Scraping of the skin may occur if the blade is not retracted. Dispose of the used blade in the closest needle disposal container. If it is not within arm’s reach, wait until the collection is complete to dispose of device. Failure to obtain blood. If you are unable to obtain sufficient blood with the first puncture, the policy at most institutions is to attempt one more puncture. You must use a sterile lancet to make the new puncture. After two unsuccessful punctures, notify the nursing station and contact a different phlebotomist to complete the procedure. Prepare to collect the sample. - Wipe away the first drop of blood with a clean gauze pad to prevent contaminating the sample with tissue fluid. Keep the finger in a downward position to help encourage blood flow. You can alternate applying and releasing firm pressure proximal to the site to increase flow, but avoid constant massaging, as this will cut off flow, cause hemolysis, and introduce tissue fluid back into the sample. Collect the sample. - Once blood is flowing freely, position the container for collection. Microcollection tubes should be slanted downward. Lightly touch the scoop of the tube to the blood drop, and allow the blood to run into the tube. Do not scrape the skin with the container. This causes hemolysis, activates platelets, and contaminates the sample with epithelial skin cells. Tap the container lightly to move blood to the bottom. Close the lid after the sample has been collected. Invert the tube 8 to 10 times after filling if additives are present. The tube must be filled with blood within 2 minutes of puncturing the skin. After that, the sample may be contaminated with excessive tissue fluid and clots. Be careful not to overfill the microcollection tube containing anticoagulant because the ratio of anticoagulant to blood will be exceeded and microclots will form. The collection will need to be repeated because of inaccurate test results. Order of collection. Platelet counts, complete blood counts (CBCs) and other hematology tests are collected first, followed by chemistry tests. Be mindful of specimens that require special handling before transport. Complete the procedure. - Apply pressure to the puncture site using a clean gauze square. Once bleeding has stopped, you can bandage the site for older children and adults. Do not use a bandage on children younger than age 2 years, as they may remove the bandage and choke on it. When drawing blood from children and infants, be especially careful that all equipment has been picked up and bed rails have been placed back in position. Label the microsample container, and place it in a larger holder for transport to the laboratory. Dispose of the puncture device if you have not done so already. As always, thank the patient. 03 POINT-OF-CARE TESTING Point-of-care Testing Point-of-care testing is the performance of analytic tests at the “point of care,” which may be at the bedside, in the clinic, or even in the patient’s home. Tests are done with small portable instruments that offer significant time and cost savings in many situations. Blood tests typically performed at the point of care (POC) include many tests in hematology, coagulation, and chemistry. In addition, the multiskilled phlebotomist may perform electrocardiography, occult blood analysis, urinalysis, pregnancy testing, and multiple tests for infectious diseases, including rapid group A Streptococcus (“strep”) and HIV. Advantages of Point-of-Care Testing Point-of-care testing (POCT) refers to the performance of analytic tests immediately after obtaining a sample, often in the same room that the patient is seen in (the “point of care”). POCT is also known as alternate site testing (AST). POCT may be performed at the bedside, in the intensive care unit or emergency room, or in outpatient settings, such as a clinic, physician’s office, nursing home, assisted living center, or the patient’s own home. The advantages of POCT are considerable. By “bringing the laboratory to the patient,” the turnaround time for obtaining test results is shortened, allowing more prompt medical attention, faster diagnosis and treatment, and potentially decreased recovery time. Most tests performed as POCT are tests waived by the Clinical Laboratory Improvement Act of 1988 (CLIA ‘88). Such tests are called CLIA waived. The U.S. Food and Drug Administration (FDA) decides which tests are CLIA waived based on the ease of performing and interpreting the test. A CLIA-waived test is not subject to regulatory oversight by government authorities. The FDA website maintains a complete list of waived tests. An essential feature of a CLIA-waived test is that the testing equipment and procedure are so simple and accurate that erroneous results are unlikely. Results are read directly from digital displays or monitors on the instrument. Although the direct cost per test is often more with these instruments, the total cost to the laboratory is often less when the time and cost for sample delivery or after-hours staffing of the laboratory are considered. As the healthcare delivery landscape changes, and as more versatile and sophisticated devices are developed, POC testing is likely to become even more widespread and is likely to be used for more tests and in more settings. Becoming familiar with the newest POCT products will help you maintain an advantage in a changing healthcare system. Tests such as bleeding times have always been done at the bedside. The significant expansion of POCT in recent years has been possible because of the development of miniaturized analytic equipment and microcomputers. Instruments used in POCT are small, portable, and often handheld, with some tests requiring no instruments, only a card or reagent strip or “dipstick.” In general, POCT instruments are easy to use, the required training is simple, and they can be used by a variety of medical professionals, including phlebotomists, nurses, nurse assistants, and physicians. Although these instruments are easy to use, the importance of carefully following the manufacturer’s instructions cannot be overemphasized. For example, some manufacturers follow the traditional method of wiping away the first drop of blood from a dermal puncture and using subsequent drops for testing. However, a few instrument makers use the first drop of blood for their procedures. Using the second drop with such instruments would give false readings, because the instrument calibration and reference ranges are based on the values from first drop of blood. Quality assurance and controls are still essential for the use of POCT instruments, just as they are with laboratory-based instrumentation. The laboratory is usually responsible for documentation and maintenance of POCT instruments. Finally, proper and adequate training for all personnel performing these procedures is critical to implement POCT successfully. Strict adherence to guidelines regarding calibrating equipment, running controls, performing maintenance, and keeping records is a must for a POCT program. Failure in any one of these areas can lead to erroneous test results and negative consequences for patients. Common Tests Performed At the Point of Care Here we discuss some of the most common POCT likely to be performed by the phlebotomist. Hematology Hemoglobin (Hgb) is the most common hematology test performed as a POC test. Hgb testing is used to diagnose and monitor anemia. A simple, fast method of anemia testing uses a handheld Hgb analyzer. Such instruments can use arterial, venous, or dermal blood specimens and typically give readouts in less than a minute. A whole blood sample is placed into a microcuvette or on a test strip, which is then inserted into the machine for a reading. The instrument determines the Hgb value in grams per deciliter (g/dL), which can be tracked over the disease course or be used to determine the response to therapy. Instruments are also available that provide readings of red blood cells (RBCs), white blood cells (WBCs), and platelets. A hematocrit (Hct) reading is sometimes made at the bedside or, more commonly, in the clinic office. Blood is collected into a microhematocrit tube and spun down quickly using a tabletop centrifuge. Results are available within 2 minutes. Coagulation Coagulation monitoring is used to monitor patients with clotting disorders who are receiving therapy. Several handheld instruments are used for bedside measurement. Some use only a single drop of whole blood obtained from a dermal puncture; others use citrated blood obtained by venipuncture. Most give results in 5 minutes or less. Heparin therapy may be monitored by determining the activated clotting time (ACT), also known as the activated coagulation time. ACT testing is done mainly during heart surgery or kidney dialysis, using an automated tester at the bedside. The activated partial thromboplastin time (APTT) can also be used to monitor heparin therapy, and a single instrument may be able to perform both tests. Oral anticoagulant therapy using warfarin (Coumadin) is monitored by the prothrombin time (PT) test. CLIA-waived PT testing instruments are frequently used in physicians’ offices and clinics. Antiplatelet medications, which are used to prevent stroke, and include aspirin and clopidogrel, may also require monitoring for their effect on coagulation. Effects of these medications can be monitored through platelet function testing, which can be performed at the bedside with an automated instrument). Chemistry Glucose Bedside glucose monitoring is the most common chemistry test done by POCT. Glucose is determined with dermal puncture and reagent strips. The specimen tested is whole blood. Ancillary Blood Glucose Test The ancillary blood glucose test is performed at the bedside, most often for patients with diabetes mellitus. Blood collected by dermal puncture is applied to a paper reagent strip or a microcuvette, depending on the instrument. Because different manufacturers have somewhat different procedures for their machines and test strips, be sure to read and understand the directions for the one you are using. Before any patient sample can be tested, the instrument must be calibrated with materials provided by the manufacturer. This is usually performed by laboratory personnel at scheduled times. Control solutions must also be run using the same procedure as for the patient’s test. These results are recorded as well. If any values fall outside the ranges provided by the manufacturer, troubleshooting must be performed until the values are correct. Proper calibration and control are critical for accurate results. Be sure to follow your institution’s instructions exactly regarding performance and frequency. Hemoglobin A1c Hgb A1c can be analyzed as a CLIA-waived test, using a handheld portable testing monitor. It can be used at the bedside or other POC, providing immediate results. An example of a CLIAwaived device is the CHEK Diagnostics A1cNow MultiTest System. These devices are designed for clinics and physicians’ offices to manage patients with diabetes. The test monitors the longterm effectiveness of diabetes therapy by providing a reading of A1c, a protein related to the average blood glucose level over a period of 4 to 6 weeks. Cardiac Troponin T and Cardiac Troponin I Cardiac troponin T (cardiac TnT) and cardiac troponin I (cardiac TnI) are part of a protein complex in cardiac muscle that aids the interaction of actin and myosin. Damaged cardiac muscle releases both TnT and TnI, and their levels may help determine the extent of damage and the patient’s prognosis. The plasma level of cardiac TnT rises within 4 hours after an acute myocardial infarction (heart attack). It may stay elevated for up to 2 weeks. TnI can be detected 4 to 8 hours following onset of chest pain. It reaches peak concentration after 12 to 16 hours, and remains elevated for 5 to 9 days. Therefore monitoring cardiac TnT and TnI can provide valuable information for a patient with a possible myocardial infarction. Bedside determination is performed using anticoagulated whole blood, and results are available within 15 minutes. Lipids Cholesterol levels may be determined as part of a routine examination or to monitor therapy with cholesterol-lowering drugs. Some POCT determinations use a one-step, disposable color card or a test strip rather than a machine. These use whole blood from either a dermal puncture or a heparinized venous sample. Blood is applied to a card, and a color determination is made after the reaction takes place. Other cholesterol POCT methods use instrumentation. Blood Gases and Electrolytes Several instruments are available that can analyze arterial blood gases (ABGs) (the concentrations of oxygen and carbon dioxide and the pH) and common electrolytes (sodium, potassium, calcium, chloride, and bicarbonate). Some systems are small enough to be handheld; others require a cart. They are particularly useful when frequent or rapid chemistry determinations must be made, such as in the emergency room or intensive care unit. Because of their complexity, all these instruments require careful calibration and more training than do simpler instruments, such as Hgb analyzers. The specimen tested is whole blood. B-Type Natriuretic Peptide B-type natriuretic peptide (BNP), also known as brain natriuretic peptide, is a hormone made by the heart in response to expansion of ventricular volume and pressure overload. Its production increases in patients with congestive heart disease (CHD). The measurement of BNP at the bedside allows the practitioner to quickly differentiate between chronic obstructive pulmonary disease (COPD) and CHD, which may have similar symptoms. BNP can also be monitored to determine the effectiveness of CHD therapy. The BNP test requires a whole blood sample collected in ethylenediaminetetraacetic acid (EDTA). C-Reactive Protein C-reactive protein (CRP) is an inflammatory marker used to monitor inflammation in autoimmune diseases and postsurgically to monitor postoperative infections. Elevated CRP is also a risk factor for heart disease, and may be a better indicator of risk than low-density lipoprotein (LDL). 04 PEDIATRIC PATIENTS Collecting blood from pediatric patients presents both technical and psychologic challenges. Because greater technical expertise is required to perform phlebotomy on children than on adults, you should master your collection methods on adult patients first. Similarly, you should master collection in older children before moving on to young children and infants. Special Physiologic Considerations Children have a lower total blood volume than adults do. The younger (and smaller) the child, the lower the volume that can be safely withdrawn. For example, a 150-lb adult has about 5 L of blood, so a 10-mL sample represents about 0.2% of total blood volume. In contrast, that same sample from a 1-year-old represents 1% of total blood volume, and in a newborn about 3%. Removal of more than 10% of total blood volume can cause cardiac arrest. Repeated withdrawal of even smaller amounts may cause iatrogenic anemia. Infants and children should not have more than 5% of their blood volume removed within a 24-hour period unless medically necessary. Removal of 3% or less is the preferred maximum. No more than 10% should be removed over a 1-month period unless medically necessary. The table below provides guidelines for determining safe volumes that may be withdrawn. The Clinical and Laboratory Standards Institute (CLSI) recommends that institutions have a process in place to monitor daily blood volume withdrawal from pediatric patients. Newborns and children have small and fragile veins that are not fully developed. Their veins are easily damaged and they are at risk of permanent damage from improper venipuncture. For this reason, dermal puncture is the best method for blood collection for pediatric patients. Dermal puncture also requires a very small amount of blood. However, it cannot be used when a larger volume of blood is required, such as for blood culture or cross-match testing or for coagulation testing. For blood culture in infants and small children, a sample of 1 to 5 mL is required. Consult with the laboratory’s procedures manual for specific information on minimum draw volumes in infants. Newborns also have a higher proportion of red blood cells (RBCs) than adults do (60% vs. 45%) and a lower proportion of plasma (40% vs. 55%), so more blood may be needed to obtain enough serum or plasma for testing. Newborns and infants are also more susceptible to infection, because of the immaturity of their immune systems. Extra precautions should be taken to avoid exposing this group to potential sources of infection. Protective isolation procedures, discussed in Chapter 4, are often used. Special Psychologic Considerations Children differ in their levels of understanding, ability to cooperate, and anxiety about medical procedures. For many children, needles represent pain, and their fear of pain often makes the collection procedure challenging for the phlebotomist. In addition to the fear of pain, children may be anxious about being in a hospital and away from home. Some children associate a white coat with all these fears, and seeing any stranger in a white coat enter the room can increase their anxiety level even before they see a needle. As a phlebotomist, your goal is to make the collection as calm, comfortable, and painless as possible for the child. Keeping the child calm not only helps the child but also helps you carry out the procedure. Prolonged crying also affects the white blood cell (WBC) count and the pH level of the blood; therefore a calm experience ensures accurate test results. Several strategies can be used to reduce the child’s anxiety. Not all of them work for every child, and some are more appropriate for children of certain ages or dispositions. As you gain experience, you will be able to gauge how to best approach each child. You can do the following to minimize the child’s anxiety: Prepare your equipment ahead of time, before you encounter the child. This means less time for the child’s anxiety to build before the stick. If possible, perform the procedure in a room that is not the child’s hospital room, such as a procedure room. This allows the child to feel safe in his or her bed. Be friendly, cheerful, and empathetic. Use a soothing tone of voice. Explain what you will be doing in terms that are appropriate for the child’s age. Even if the child will not or cannot respond, your explanation helps the child understand what is about to happen, lessening the fear of the unknown. Demonstrating on a toy can be helpful. Do not say that it will not hurt. Rather, explain that it will hurt a little bit and that it is okay to say “ouch” or even to yell or cry, but emphasize the need to keep the arm still. Give the child choices whenever possible to increase his or her feeling of control. You can ask the child which arm or finger to use or which type of bandage he or she prefers. This also keeps the child occupied, lessening anxiety. Use the shortest possible needle for the procedure, and keep it out of sight for as long as possible. Distract the child just before the actual stick so that he or she is looking away. If parents or siblings are in the room, they can be helpful here. During the draw, tell the child how much longer it will be (“just one more tube” or “a few more seconds”). This can help keep the child’s anxiety from building during the procedure. Afterward, praise the child (even if he or she did not cooperate as well as you had hoped) and offer him or her a small reward, such as a sticker (for younger children) or a pencil (for older children). Involvement of Parents and Siblings Parents who are present during the procedure can help in several ways. Ask the parent whether the child has had blood drawn previously and, if so, what techniques helped ease the child’s anxiety. Parents or siblings can help distract and comfort the child. Siblings should be offered small rewards as well. Some parents may prefer not to remain with the child during the procedure because they are reluctant to see the child in pain or become queasy at the sight of blood. Respect their wishes. In some cases, parents can make the child more anxious through their words or reactions. If you feel that the parents cannot help the child, you can politely suggest that they might be more comfortable waiting outside. If the child needs restraining, check your employer’s policy regarding the use of restraints. Identification of Newborns On their identification (ID) bracelets, newborns may be identified only by their last names, such as “Baby Boy (or Girl) Smith.” As always, use the hospital ID number, not the name, as the ultimate proof of ID. Be especially careful with twins, who are likely to have similar names and ID numbers. Supplies When performing venipuncture, use shorter needles, if possible, and use the smallest gauge consistent with the requirements of the tests. Butterfly needles and smaller, partial-fill tubes should be used for pediatric draws. You will need additional protective equipment in the premature nursery (and possibly in the full-term nursery) to reduce the risk of spreading infection. Check with the nursery supervisor regarding policy. Take along a selection of rewards, such as stickers or small toys. Keep a stock of cartoon bandages as well. In a pinch, you can draw a smiley face on a regular bandage. Remember not to use these on infants younger than 2 years because of the danger of choking. Anesthetics Topical anesthetic cream may be useful for venipuncture procedures in pediatric patients. The most commonly used agent is EMLA (eutectic mixture of local anesthetics), a mixture of lidocaine and prilocaine. It must be applied 60 minutes before the draw, however, which means that the site must be chosen at that time. It is possible to numb more than one area if it is not practical to choose the site ahead of time. Anesthetic is not recommended for phenylketonuria (PKU) testing (described later). Some states and institutions do not allow phlebotomists to apply any medication—check with your institution first. Sucrose solutions can also be used to reduce pain and crying time in newborns and infants under 6 months. The solution is a mixture of 25% sucrose (table sugar) in water. The solution is administered orally with a syringe, dropper, nipple, or a pacifier. The solution is given 2 minutes before the puncture and reduces pain and calms the child for about 5 minutes. Immobilization of Infants and Children Immobilizing pediatric patients may be necessary to ensure their safety during the draw. Wrapping newborns or very young infants in a receiving blanket is usually sufficient, as they are not strong enough to work themselves loose during the procedure. Older babies, toddlers, and young children need to be restrained. Know your employer’s restraint policy. Older children may have the self-control to keep from moving, but a parent’s care and attention can still be beneficial during the draw. Pediatric draws are done with the patient either seated in the lap of a parent or other assistant or lying down, with the parent or assistant leaning over the child. For a seated child, the parent hugs the child’s body, crosses his or her legs around the child’s legs to prevent kicking and holds the arm not being used in the draw. For a child lying down, the parent or assistant leans over the child, holding the unused arm securely. The assistant may support the arm from behind, at the bend in the elbow, which helps immobilize the arm. Pediatric Dermal Puncture The procedures for dermal puncture were discussed above. As you learned earlier, heel puncture is preferred for children younger than 1 year, because the tissue overlying the finger bones is not thick enough for safe collection there. Special Considerations Several special considerations apply when performing dermal punctures in newborns and young children: The ID band must be present on the infant. Be sure to match the ID number to the number on the requisition. Keep your equipment out of the patient’s reach. Warm the heel for 3 to 5 minutes, using a heel-warmer packet. The packet contains sodium thiosulfate and glycerin, which undergo a chemical reaction when activated by squeezing. Wrap the packet in a towel before placing it against the skin. At the end of the procedure, be sure to remove all equipment from the crib and secure all bed rails in the up position. Avoid using adhesive bandages. Document the collection in the nursery log sheet. Record the date, time, and volume of blood collected. Special Dermal Puncture Procedures Neonatal Bilirubin Bilirubin is a substance produced by the normal breakdown of RBCs. The liver is responsible for further processing of bilirubin so that it does not reach excessive levels in the blood. In newborns, the liver may not be developed enough to prevent bilirubin from accumulating in the blood. When this occurs, blood must be collected to assess the patient’s clinical response to treatment to decrease bilirubin blood levels. Excess bilirubin levels commonly occur when mother and child have mismatched blood groups and antibodies from the mother break down the infant’s RBCs, increasing bilirubin levels beyond the infant’s capacity to process it. Buildup of bilirubin causes jaundice, or yellowing of the skin, and can lead to brain damage if untreated, a condition called kernicterus. When bilirubin is slightly above normal in a newborn, a Bili light, or ultraviolet light treatment, can be used. Higher levels, or levels that are rising rapidly, require blood transfusion. Collection Precautions Keep the following points in mind when collecting blood for bilirubin testing: Bilirubin is light sensitive. Bili lights should be turned off during collection. The specimen should be shielded from light using an amber-colored container, foil, or heavy paper to cover the container. Once the specimen is collected and shielded from the light, turn the Bili light back on. Hemolysis of the specimen falsely lowers the results, so precautions against hemolysis must be taken. Collection times must be recorded exactly to track the rate of bilirubin increase. Samples for bilirubin testing are frequently collected as timed or short turnaround time (stat) specimens. Neonatal Screening Neonatal screening or Newborn Screening tests are required as a part of mandatory, statebased public health programs. The tests are used to detect inherited metabolic disorders that cause severe brain damage or other impairments, and allow for implementation of early intervention treatments. In 2006 the American College of Medical Genetics recommended standardization of 29 core conditions to be tested for in all infants. The 29 core conditions were adopted the same year by the U.S. Secretary of Health and Human Services. These tests include screening for hypothyroidism and PKU. Other diseases screened for include galactosemia, homocystinuria, maple syrup disease, and biotinidase deficiency. Sickle cell anemia is an inherited disorder of the hemoglobin molecule that may also be screened for in newborns from ethnic groups with the highest risk. Each state has the authority to determine what additional tests will be included with the 29 core conditions. Specimen Collection Blood for neonatal screening is collected by capillary heel stick on special filter paper. Recent studies have shown that the levels of phenylalanine are significantly different between capillary and venous samples. Reference values are based on capillary values. The filter paper is supplied in a kit provided by the state agency responsible for screening tests. Both the ink and the paper are biologically inactive. When using the paper, do not touch or contaminate the area inside the circles, because this will alter the results. To collect a sample for neonatal screening, first perform a routine heel stick. Wipe away the first drop of blood, and then apply one large free-flowing drop of blood directly to the circle. The drop must be evenly spread. Do not touch the paper against the puncture site, and do not apply successive drops onto a single circle. Although applied to only one side of the filter paper, the blood should be visible from both sides. Air-dry the specimen on a dry, clean, flat, horizontal nonabsorbent surface for a minimum of 3 hours. Keep it at room temperature and away from direct sunlight until it is delivered to the laboratory. Causes for rejection include: use of expired specimen collection card collection date missing QNS (quantity not sufficient) blood submitted blood not completely soaked through the filter paper Contaminated or discolored specimen blood is caked, clotted, or layered on the filter paper circles patient demographic information missing form number does not match that of the blood circles specimen is too old on receipt (received 14 or more days after collection) requisition form received but no blood sample specimen submitted on improper collection form improper drying or collection resulting in serum separation specimen torn or damaged during transit laboratory accident Venipuncture in Newborns When a larger volume of blood is required, blood can be collected from newborns or children younger than 2 years by venipuncture of the dorsal hand veins. Special considerations include the following: No tourniquet is needed. Instead, clasp the infant’s wrist between your middle finger and forefinger, and allow the infant to encircle your thumb with his or her fingers. Flex the wrist gently downward while you examine the dorsal surface of the hand. Using a winged butterfly infusion with a 23-gauge needle and a syringe or pediatric evacuated tube, gently insert the needle 3 to 5 mm distal to the vein, slowly advancing until you see blood in the hub of the needle. Once blood begins to flow, you can release your hold on the needle and use your free hand to pull gently on the syringe. An alternative to using a syringe and tubes is to let the blood freely flow in to appropriate microtainer tubes. After withdrawing the needle, apply firm pressure with sterile gauze until the bleeding stops. Do not apply a bandage because the child may remove it and put it in his or her mouth. Follow the procedure for using a blood transfer device to fill required tubes and dispose of used devices. Record the volume of blood collected per your facility’s protocol. Scalp vein venipuncture can be used when other venipuncture sites are not accessible. The scalp vein is located by applying a large rubber-band tourniquet around the scalp at the level of the forehead and shaving the hair, if necessary. This procedure requires additional training and expertise. SOURCE: Warekois, Robin, S. et al. Phlebotomy. Available from: Pageburstls, (5th Edition). Elsevier Health Sciences (US), 2020.