Assisting in Blood Collection PDF

Preview

Summary

Phlebotomy...

Description

Chapter 46: Assisting in Blood Collection Introduction to Phlebotomy     

The practice of drawing blood Used primarily to diagnose and monitor a patient’s condition Training requirements to perform blood drawing It is important that medical assistants become familiar with the guidelines of their home states. What is the most common method of obtaining blood? (It is venipuncture, in which the blood is taken directly from a surface vein.)

Venipuncture Equipment              



Double-pointed safety needles Evacuated, stoppered tubes Needle holder Sharps container Winged infusion sets (butterfly needles) Syringes Tourniquet Marking pen Alcohol swabs Gauze pads Bandages Gloves These supplies are generally carried in a portable tray. Where is venipuncture usually carried out? (A physician office laboratory often has a permanent location where venipuncture is performed. In such cases, you likely will seat the patient in a venipuncture chair, which has an adjustable locking armrest to protect the patient if he or she should faint.) Figure 46-1 shows a fully stocked venipuncture tray.

Personal Protective Equipment  

  

Vinyl gloves available if the patient or phlebotomist has a latex allergy Gloves may put on after vein palpation, but before the preparation of site Tourniquet should be tied no longer than 1 minute Employers must provide employees with gloves, including the hypoallergenic, powderless, and vinyl types, as needed. OSHA requires that healthcare workers wear gloves during venipuncture.

Tourniquets

Chapter 46: Assisting in Blood Collection    



Figure 46-3 shows an example of a latex-free nitrile tourniquet. Tourniquet is tied around upper arm so that it is tight, but not uncomfortable, to make veins bulge. Tourniquets are applied 3 to 4 inches above the elbow immediately before the venipuncture procedure begins. What are some ways to be sure the tourniquet is applied correctly but as comfortably as possible? (Checking the pulse at the wrist ensures that arterial flow is not restricted. Make sure the tourniquet is flat against the skin, and if necessary, tie it over the clothing if it is causing the patient discomfort.) What happens if you leave on a tourniquet for more than a minute? Why? (Because it impedes blood flow, leaving it on for more than 1 minute greatly increases the possibility of hemoconcentration.)

Antiseptics 

 

Venipuncture site must be cleansed with an antiseptic o The most common type is 70% isopropyl alcohol Alcohol should remain on the skin 30 to 60 seconds When is the use of an isopropyl square prep pad contraindicated? (Isopropyl alcohol should not be used when a sample for a blood alcohol test is drawn. Sterile soap pads, benzalkonium chloride, or povidone-iodine [Betadine] can be used instead. If a blood culture is ordered, additional preparation is needed at the venipuncture site to eliminate contaminating bacteria. Povidone-iodine solution commonly is used, and chlorhexidine gluconate or benzalkonium chloride can be used for patients allergic to iodine.)

Evacuated Collection Tubes     



Evacuated tube (Vacutainer) system consists of evacuated tubes of various sizes that have color-coded tops Vacuum in each tube draws a measured amount of blood into tube Be sure to match the needle gauge to size of tube Consult manual provided by laboratory to make sure you are drawing right amount of blood for test How can you allay a patient’s fears when several vials of blood need to be drawn? (Explain that the average adult has a little less than 10 pints of blood [5 L]. Most adults can relate to donating a unit of blood, which is around a pint [400 to 500 mL]. Because the red-topped tube contains 10 mL, you would have to draw 40 to 50 tubes before you have removed a pint.) Refer students to Table 46-1 for the common stoppers and their laboratory uses.

Tube Additives

Chapter 46: Assisting in Blood Collection 





All tubes except the red-topped ones contain an additive o Anticoagulants are added to prevent blood from clotting o Ethylenediaminetetraacetic acid (EDTA) prevents platelet clumping and preserves the appearance of blood cells for microscopic examination o Clot activators promote blood clotting How do anticoagulants allow blood to be used in two ways? (First, the sample can be used as whole blood; second, the sample can be centrifuged, and the liquid portion, called plasma, can be retrieved.) What effect does clotting have on centrifugation? (If blood is allowed to clot and then is centrifuged, the liquid portion is referred to as serum. Without a clot activator, blood clots in 30 to 60 minutes, after which it must be centrifuged. Thixotropic gel can be found in some tubes and it settles between the two layers during centrifugation, forming a barrier that facilitates retrieval of the liquid portion without cellular contamination.)

Stopper Color and Inversion Mixing  

Table 46-3 shows stopper color and inversion mixing. It is important to mix the contents of the tube well after collection by inverting it several times (do not shake the tube) and also to avoid a short draw (i.e., a tube that is not completely filled.)

Order of Collection 

  

      

Specified order must be followed so that material from previous tube is not transferred to the next tube Carryover of additives can alter samples and cause result errors Same order applies to filling of tubes when blood is collected in syringe The Clinical and Laboratory Standards Institute (CLSI) (formerly the National Committee for Clinical Laboratory Standards [NCCLS]) developed a set of standards outlining the order of draw for a multitube draw. Yellow blood culture tubes first (sterile) Light blue-topped tubes with sodium citrate Red serum tubes with red or red-gold or speckled stopper Green-topped tubes Lavender-topped tubes Gray-topped tubes Same order applies to filling of tubes when blood is collected in syringes.

Types of Needles and Supplies Used in Phlebotomy

Chapter 46: Assisting in Blood Collection      

Know which needle and which tube or syringe should be used in each situation All needles used in phlebotomy are sterile, disposable, and used only once Inspect each needle cover for intact seal Hub, shaft with bevel, and lumen (hole) make up needle Gauge of lumen; higher number for smaller lumen Discuss the relationship between gauge and size of lumen, or opening, of the needle. (The gauge is designated by a numeric value; the higher the number, the smaller the lumen. A blood bank uses a 16-gauge needle to collect pints of blood for transfusions because the lumen is wide, which reduces the chance of hemolysis. The smallest-gauge needles [23 gauge] are used to collect blood from small or fragile veins, such as those found in elderly and very young patients.)

Multisample Needles   

Figure 46-5 shows multisample needles. Commonly used in routine adult venipuncture; so called because they are used when several tubes are to be drawn during a single venipuncture. They are double-pointed; one point enters the patient’s vein, and the other punctures the rubber stopper of the collection tube.

Needle Holders 





Figure 46-6 shows a vacuum system. Left, Vacutainer tube. Right, needle holder with multisample needle attached. Double-pointed needles must be firmly placed into a needle adaptor or tube holder. OSHA requires that the needle holder, with the safety-activated needle still attached, be discarded into the biohazard sharps container immediately after withdrawal from the vein.

Syringes 



  

Used when there is a concern that strong vacuum in a stoppered tube might collapse the vein Syringe needle fits on the end of the barrel and comes in different gauges Must be transferred immediately to another tube or it will clot in syringe barrel Special transfer tube adapter is used to transfer blood to Vacutainer tube The adapter connects to the top of the syringe once the needle cover is in place and the needle is removed.

Chapter 46: Assisting in Blood Collection BD Vacutainer Blood Transfer Device 



Figure 46-7 is a BD Vacutainer blood transfer device, showing the blood from the syringe above about to be pulled into the vacuum tube on the bottom when the vacuum tube is pushed into the holder. The adapter contains an enclosed needle that punctures and delivers the blood into the Vacutainer tube.

Winged Infusion Set (Butterfly Needles) 

 

Figure 46-8 shows a winged infusion (butterfly) set with sterile tubing containing a white Luer needle adapter that will attach to a syringe, and a Vacutainer-sheathed needle that will attach to a Vacutainer holder. Butterfly needles are designed for use on small veins, like in the hand or in children. How does this type of needle work? (The most common needle size is 23 gauge; the needle is ½ to ¾ inch long and has a plastic, flexible, butterfly-shaped grip attached to a short length of tubing. One end is fitted into the syringe or the vacuum tube adapter.)

Needle Safety 





Needle injuries can lead to serious or fatal infections with blood-borne pathogens such as hepatitis B virus (HBV), hepatitis C virus (HCV), or human immunodeficiency virus (HIV) Best practice for preventing needlestick injuries after phlebotomy is to use a sharp with safetyengineered sharps injury protection (SESIP) attached to a needle holder SESIPs, or safety needles, eliminate the need to remove the needle from the needle holder and in some way shield the needle immediately after use.

Examples of Needle Safety Devices     

One-handed Vacutainer needles Syringe needle safety devices Butterfly needles safety lock Push-button butterfly safety device Needle blunting butterfly set

Chapter 46: Assisting in Blood Collection Steps to Protect Against Needlesticks           

Do not use needles when safe, effective alternatives are available Help your employer select and evaluate devices with safety features Use devices with safety features provided by your employer Never recap a contaminated needle Plan for safe handling and disposal before beginning any procedure using needles OSHA requires employers to establish and maintain a sharps injury log for recording injuries from contaminated sharps. Dispose of used needles and needle holders promptly in sharps disposal containers Report all needlesticks and other sharps-related injuries promptly Tell your employer about hazards from needles that you observe in your work environment Participate in blood-borne pathogen training and follow recommended infection prevention practices, including obtaining hepatitis B vaccination What should the sharps injury log include? (This log should contain information about the device involved in the incident and the department or work area where the incident occurred, as well as an explanation of the incident. Employee confidentiality must be maintained.)

Postexposure Management of Needlesticks     

Wound inspected and washed for 10 minutes with antimicrobial soap or antiseptic Reported to supervisor and incident report completed Referred to physician for confidential assessment and follow-up care Interim testing may be performed, and counseling should be offered What steps are taken during the assessment and follow-up care stage of the process? (Baseline testing for HBV, HCV, and HIV is recommended for both the employee and the source individual. If the source tests positive or cannot be tested, the employee may be treated with prophylactic care to prevention infection.)

Patient Preparation for Venipuncture 



Requisition form should include: o Patient’s name o Date of birth o Identification number o Name of the physician making the request o Type of test requested o Test status (timed, fasting, stat, and so forth) How is the venipuncture process begun? (Venipuncture begins with greeting and identifying the patient. According to CLSI, proper identification includes asking outpatients to provide their full name and address, and an identification number or birth date. This information must be compared with

Chapter 46: Assisting in Blood Collection the written information on the requisition. Introduce yourself and briefly explain the purpose and procedure of the venipuncture. Obtain verbal consent to perform the procedure and use a confident and respectful tone.) The Veins of the Forearm  

Figure 46-14 shows the veins of the forearm. Generally, veins in the forearm or the elbow (antecubital area) are used for venipuncture.

Preparing for the Venipuncture  Seat patients (or have them lie down) and ask them to extend the arm

Chapter 46: Assisting in Blood Collection

  





o Inspect arms and ask if they have a preference and select vein o Other sites may be used, like the back of a hand or foot if necessary Place the tourniquet 3 to 4 inches above the elbow Have patients make fist and palpate for vein The medial veins generally run parallel or at a slight angle to the fold in the antecubital area, whereas the cephalic veins run lateral or to the outside of the antecubital area. If the patient complains of tingling, numbness, or a shooting pain, discontinue the procedure and choose another site before continuing. What are the steps involved with a venipuncture? (The first step is to select the proper method for venipuncture [syringe or evacuated tube]. Next, the patient must be prepared for the procedure. Patient preparation is followed by the actual venipuncture and specimen collection. The final step is care of the puncture site before the patient is discharged.)

Placement of a Tourniquet  

Figure 46-15 shows placement of a tourniquet. How is the tourniquet put into place? (Grasp the tourniquet ends, one in each hand, at the part of the tourniquet that is closest to the patient’s skin. Pull the ends apart to stretch the rubber material, then cross one end over the other while maintaining the tension. Tuck the top end of the tourniquet underneath the bottom piece, creating a loop with the upper flap free so it can be released with one hand.)

Performing the Venipuncture          

Remove the tourniquet after locating a vein Assemble all equipment needed, open sterile packets, sanitize hands Reapply the tourniquet to quickly relocate a vein Put on gloves, cleanse the antecubital area with alcohol, have the patient clench fist Anchor the vein and insert needle into vein at 15-degree angle Pull back on the syringe plunger or push the evacuated tube into a doublepointed needle How is the vein "anchored"? (Stretch the skin downward below the collection site with the thumb of your nondominant hand.) When blood enters the tube or barrel, ask patient to unclench the fist. Procedure 46-1 describes the procedure for collecting a venous blood sample using the vacuum tube method. Procedure 46-2 describes the procedure for collecting a venous blood sample using the syringe method.

Chapter 46: Assisting in Blood Collection Completing the Venipuncture       

Continue to draw the specimen, filling each tube Invert each tube several times after removal, before placing it in the rack Near the end of the draw, release tourniquet and remove final vacuum tube Remove needle quickly, and apply gauze and pressure to site Activate safety device to cover needle Bandage when the bleeding stops What are some important things to remember once you have removed the needle? (Observe site for 5 to 10 seconds after applying pressure and gauze to be sure the bleeding has stopped. Label all the tubes by the patient’s side; do not leave the room before labeling the samples. Follow steps for sharps disposal.)

Winged Infusion Set (Butterfly Needle) 

 

Used with children and elderly patients due to their narrow veins o The tubing minimizes the strength of the vacuum, which prevents the collapse of fragile veins Also used to draw blood from the hands of adults Procedure 46-3 describes how to obtain a venous sample with a safety winged butterfly needle.

Problems Associated with Venipuncture    

 

Hematoma (bruise) at puncture site o Discontinue procedure, apply pressure and then ice Fainting (syncope) Nerve damage is uncommon; avoid basilic vein and blind probing The most common causes of hematoma formation during the draw are excessive probing with the needle to locate a vein, failure to insert the needle far enough into the vein, and a needle that goes through the vein. It is wise to limit yourself to two attempts to obtain blood from any one patient. Refer to Table 46-4 to view how to manage possible blood draw complications.

Specimen Re-Collection       

Unlabeled or mislabeled specimen Insufficient quantity Defective tube Incorrect tube used for the test ordered Hemolysis Clotted blood in an anticoagulated specimen Improper handling

Chapter 46: Assisting in Blood Collection   

These are some of the common reasons for a laboratory-rejected specimen. What is the major cause of rejected specimens? (Hemolysis) Refer students to Table 46-5 for the major causes of hemolysis.

Capillary Puncture       

    

Older patients Pediatric patients (especially younger than age 2) Patients who require frequent glucose monitoring Patients with burns or scars in venipuncture sites Obese patients Patients receiving intravenous therapy Capillary, or dermal, puncture is an efficient means of collecting a blood specimen when only a small amount of blood is required or when a patient’s condition makes venipuncture difficult. Patients who have had a mastectomy Patients at risk for venous thrombosis Patients who are severely dehydrated Tests that require a small volume of blood Because capillaries are bridges between arteries and veins, capillary blood is a mixture of the two.

Skin Puncture Devices: Lancets 

 



Figure 46-16: Skin puncture devices (lancets) include safety needles (blue and white) and safety blades (green and pink) that control the depth and width of the incision. Both types automatically retract after use. The lancet delivers a quick puncture to a predetermined depth. OSHA has directed that lancets must have retractable blades and locks to prevent puncture after use. They must always be discarded in a sharps container.

Collection Containers 



Figure 46-17: Pink lancet is to the left of the white container containing selfsealing capillary blood collection tubes (seen in the middle). Top right, another lancet above three color-coded Microsample containers. Discuss the different types of collection tubes. (Microcollection, or Microtainer, tubes hold up to 750 L [0.75 mL] of blood, are color-coded, and are available with a variety of anticoagulants and additives. Capillary tubes draw blood into them without the need for suction.)

Chapter 46: Assisting in Blood Collection Lancet Blade Recommendations 

Discuss the depth and dimension, blood volume, and application for lancet blade recommendations that are listed in Table 46-6.

Guthrie Cards  Blood from a capillary puncture also can be deposited on paper cards.  Figure 46-18: A, Guthrie card used in neonatal screening. B, Correct and incorrect ways to fill in the circles.  Blood is deposited into circles on biologically inactive filter paper ...