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Chapter 17
Chapter 17 Phlebotomy
| Question | Answer |
|---|---|
| What is the purpose of phlebotomy? | To collect a blood specimen for laboratory analysis |
| List the three major areas of blood collection and the type of specimen obtained? | Arterial puncture- for collection of an arterial blood specimen. Venipuncture- for collection of a venous blood specimen. Skin puncture- for the collection of a capillary blood specimen. |
| What two methods can be used to perform a venipuncture? | vacutainer method and butterfly method |
| What are the advantages of using the Vacutainer method of venipuncture? | Is the fastest and most convenient method and is most often used |
| When is the butterfly method used for venipuncture? | Used for difficult draws, such as when a vein is small or sclerosed (hardened) |
| What reference source should be consulted to determine the collection and handling requirements of tests performed at an outside laboratory? | Laboratory test directory |
| Why should a patient be identified using two unique identifiers? | To avoid collecting a specimen from the wrong patient by mistake, which could lead to an inaccurate diagnosis and wrong treatment |
| What might occur if the wrong collection tube is used to collect a blood specimen? | Will not yield the proper type of specimen required for the test |
| What occurs if an expired collection tube is used to collect a blood specimen? | Outdated tubes may no longer contain a vacuum and as a result they would not be able to draw blood into the tube. If expired tube is used the specimen would be rejected from the outside laboratory. |
| What is the purpose of a laboratory request? | Provides the outside laboratory with the information necessary for accurate testing, reporting a results, and billing |
| How should a barcode label be placed on a blood collection tube and why? | Place lengthwise on the tube and aligned with the top of the manufacturer's label and no higher. Enables the barcode reader to read the label |
| Why should the patient be notified right before the needle is being inserted? | Prevents startling the patient, which could cause the patient to move |
| Explain how to prevent venous reflux? | Keep the patient's arm in a downward position, so that the collection tube remains below the venipuncture site and fills from the bottom up |
| What is the purpose of a tourniquet? | Makes the patient's veins stand out so that they are easier to palpate |
| What may occur if the tourniquet is too tight? | Is uncomfortable for the patient; it also obstructs both venous and arterial blood flow |
| What may occur if the tourniquet is too loose? | Fails to cause the veins to stand out enough to palpate |
| What can occur if the tourniquet is left on the patient's arm for longer than a minute? | Causes the venous blood to stagnate or pool in one part too long a condition known as venous stasis |
| What occurs if the venipuncture needle is removed before the tourniquet? | The pressure of the tourniquet causes blood to be forced out of the puncture site and into the surrounding tissues resulting in a hematoma |
| Why are the antecubital veins preferred for performing a venipuncture? | They typically have a wide lumen and are close to the surface of the skin which makes them easily accessible. They have thick walls making them less likely to collapse |
| What are the advantages of using the median cubital vein as a venipuncture site? | Is a prominent vein and does not roll. Spares patient unnecessary pain because the skin is less sensitive |
| What should be determined through palpation after a suitable vein has been located? | The size, depth, and direction of the vein |
| List techniques that can be used to make veins more prominent? | Remove the tourniquet & have the patient dangle arm over the side of the chair for 1 to 2 min. Tap the vein site sharply a few times with your index finger & 2nd finger. Massage the arm from wrist to the elbow. Apply a warm washcloth for 5 min to the area |
| Why should the veins of the hand be used only as a last resort for venipuncture? | They have a tendency to roll making them more difficult to stick. Abundant supply of nerves is present in the hands which makes it uncomfortable for the patient. They tend to have thin walls which makes them susceptible to collapsing, bruising & phelbitis |
| How is a serum specimen obtained? | Uses a tube that does not contain an anticoagulant (ex. SST or red tube). Is obtained from clotted blood by allowing the specimen to stand and then centrifuging it. |
| How is a whole blood specimen obtained? | By using a tube that contains an anticoagulant. Must be inverted 8 to 10 times after collection |
| List the three layers into which blood separates when it is mixed with an anticoagulant: | Top layer- plasma Middle layer- buffy coat Bottom layer- red blood cells |
| List the layers into which blood separates when an anticoagulant is not added to it: | Top layer- serum Bottom layer- clotted red blood cells |
| What needle gauges are used for the vacutainer method and when is each used? | 21 gauge is used most often for a routine venipuncture. 22 gauge is recommended for children and adults with small veins. |
| What is the purpose of the flange on the plastic holder of the vacutainer system? | Assist in the insertion and removal of the collection tubes and prevents the tube holder from rolling when it is placed on a flat surface |
| What additive is present in the red collection tube? | No additive present or may contain clot activator |
| What additive is present in the gold and marbled red/gray tube? | Serum separator gel and contains a clot activator |
| What additive is present in the light blue collection tube? | Contains an anticoagulant sodium citrate |
| What additive is present in the lavender collection tube? | Contains anticoagulant EDTA |
| What additive is present in the green collection tube? | Contains the anticoagulant heparin |
| What additive is present in the gray collection tube? | Contains sodium fluoride (a preservative) and potassium oxalate (anticoagulant) |
| What additive is present in the royal blue collection tube? | Contains either EDTA or no additive at all |
| What color stopper must be used to collect the blood specimen for a CBC? | Lavender |
| What color stopper must be used to collect the blood specimen for prothrombin time? | Light blue |
| What color stopper must be used to collect the blood specimen for oral glucose tolerance test? | Gray |
| What color stopper must be used to collect the blood specimen for most blood chemistry test? | Gold & marbled red/gray (tiger top) |
| What color stopper must be used to collect the blood specimen for blood gas determinations? | Green |
| What color stopper must be used to collect the blood specimen for a lead test? | Royal blue |
| What color stopper must be used to collect the blood specimen for a blood alcohol test? | Gray |
| Why is it important to use the correct order of draw when performing a venipuncture? | Avoids cross-contamination of the specimen by additives found in different tubes |
| Why is it important to mix a tube containing an anticoagulant immediately after drawing it? | Because it may result in clotting of the blood leading to incorrect test results |
| What are the ranges for the gauge and length of needle used for the butterfly method of venipuncture? | Ranges from 21 gauge to 23 gauge and the length of the needle ranges from 0.5 to 0.75 inch |
| What sites should be avoided when performing a venipuncture? | If the patient complains of pain or soreness at the site. Any skin areas that are scarred, burned, bruised, or adjacent to areas of infection should not be used or an arm with edema |
| How can the cephalic and basilic veins be prevented from rolling during a venipuncture? | Apply firm pressure below and to the side of the vein to stabilize it as the needle is inserted |
| What is typically observed when performing a venipuncture on a vein that collapses? | A small amount of blood enters the tube and then stops |
| What are three ways in which a hematoma can occur? | A needle that is inserted too far and goes through the vein. A bevel opening that is partially in the vein and partially out of the vein. Insufficient pressure applied to the puncture site after removal of needle. |
| List ways to prevent a blood specimen from becoming hemolyzed? | Store collection tubes at room temperature. Allow alcohol to air dry completely before performing the venipuncture. Use an appropriate gauge needle. Practice good technique in collecting the specimen. Always handle the collection tube carefully. |
| What should be done if the patient experiences dizziness or fainting during or after a venipuncture? | The tourniquet and needle need to be removed and the patient's head needs to be lowered between their legs |
| List examples of substances dissolved in the serum of blood? | Glucose, cholesterol, sodium, potassium, chloride, antibodies, hormones, and enzymes |
| What is the proper size tube that must be used to obtain the serum specimen of 2 mL? | 5 mL |
| What is the proper size tube that must be used to obtain the serum specimen of 6 mL? | 15 mL |
| What is the proper size tube that must be used to obtain the serum specimen of 4 mL? | 10mL |
| What is the fibrin clot and why should it be avoided in a serum specimen? | Is a spongy substance that occupies space, interfering with adequate serum collection. Leaching of the substance changes the integrity of the serum |
| How does the serum separator tube function in the collection of a serum specimen? | During centrifugation the gel temporarily becomes fluid and moves to the dividing point between the serum and clotted cells, where it reforms into a solid gel serving as a physical barrier between serum and the clot |
| What is the preferred site for a skin puncture for an adult? | Lateral part of the tip of the third or fourth finger |
| What is the preferred site for a skin puncture for an infant? | Lateral or medial planter surface of the heel |
| Why is it important not to penetrate the skin too deeply when performing a skin puncture? | The bone may be penetrated, which could result in painful and serious conditions like osteochondritis and osteomyelitis |
| How is blade length determined for a skin puncture? | How big the patient's fingers are and how much blood is needed for the specimen |
| What are two examples of microcollection devices? | Microcollection tubes and capillary tubes |
| Why should a finger puncture not be performed on the index finger? | Is more calloused which makes it harder to penetrate than the other fingers. Also, the patient uses that finger more and would notice the pain longer. |
| The surface of the arm in front of the elbow | Antecubital space |
| A substance that inhibits blood clotting | Anticoagulant |
| A thin, light-colored layer of white blood cells and platelets that lies between the top layer of plasma and the bottom layer of red blood cells when an anticoagulant has been added to the blood specimen | Buffy coat |
| A sterile glass or plastic blood collection tube with a color-coded closure that contains a vacuum | Evacuated collection tube |
| A swelling or mass of coagulated blood caused by a break in a blood vessel | Hematoma |
| An increase in the concentration of the nonfilterable blood components in the blood vessels, such as red blood cells, enzymes, iron, and calcium as a result of a decrease in the fluid content of blood | Hemoconcentration |
| The breakdown of blood cells | Hemolysis |
| Inflammation of bone and cartilage | Osteochondritis |
| Inflammation of the bone or bone marrow as a result of bacterial infection | Osteomyelitis |
| A healthcare professional trained in the collection of blood specimens | Phlebotomist |
| Incision of a vein for the removal of blood; the collection of blood | Phlebotomy |
| The liquid part of the blood consisting of a clear straw-colored fluid that comprises approximately 55% of the blood volume | Plasma |
| Plasma from which the clotting factor fibrinogen has been removed | Serum |
| Puncturing of a vein | Venipuncture |
| The backflow of blood (from a collection tube) into the patient's vein | Venous reflux |
| A temporary cessation or slowing of the venous blood flow | Venous stasis |
| An arterial puncture is typically performed in a hospital to assess the | Oxygen level, carbon dioxide level, and acid-base balance of arterial blood |
| Venipuncture is usually performed in the medical office using the following methods: | Vacutainer method and butterfly method |
| The vacutainer setup consists of: | A blood collection needle, a plastic tube holder, and a evacuated collection tube |
| The word phlebotomy is derived from the Greek words for vein and incision which are | vein- "phlebos" & incision- "otomy" |
| The medical assistant should carefully review the collection and handling requirements in the laboratory test directory for the test ordered by the provider these include: | Collection supplies necessary, the type of specimen to be collected, the amount of specimen needed to perform the laboratory test, the procedure to follow to collect the specimen, and the proper handling and storage of the specimen awaiting transport |
| After greeting the patient the medical assistant should ask the patient: | To state his or her full name and date of birth |
| The medical assistant should check each blood collection tube before use to ensure that it is not: | Broken ,chipped, cracked, or otherwise damaged, or expired |
| A handwritten label for a blood specimen requires what information: | Patient's full name and date of birth, the date and time of collection, the medical assistant's initials, and any other information required by the laboratory |
| Just before inserting the needle tell the patient that he or she will | "Feel a small stick" |
| Proper positioning of the patient's arm allows: | Easy access to the vein and is more comfortable for the patient |
| The most common site for the venipuncture is the | Antecubital space |
| Venipuncture should never be performed with the patient | Sitting on a stool or standing |
| If the patient appears nervous or has fainted in the past from a venipuncture it is best to place the patient | In a semi-reclining position (semi Fowler position) on the examining table |
| Venous reflux is prevented by | Keeping the patient's arm in a downward position, so that the collection tube remains below the venipuncture site and fills from the bottom up |
| What makes the patient's veins stand out so that they are easier to palpate? | Tourniquet |
| What are the guidelines for applying a tourniquet? | Don't apply over sores or burn skin. Hold each end of the tourniquet with one hand. Position the tourniquet 3 to 4 in. above the bend of the elbow. Never leave on longer than 1 min. Remove as soon as good blood flow is estab. Always remove before needle |
| The best vein to use in the antecubital space is the? | Median cubital |
| Why is the median cubital vein the best to use for venipuncture? | It is a prominent vein in the middle of the antecubital space and does not roll |
| Is located on the thumb side of the antecubital space and is the second best choice for venipuncture | Cephalic vein |
| Is considered the third best choice and is located on the little finger side of the antecubital space | Basilic vein |
| If it is impossible to locate a suitable vein in the antecubital space alternative sites are available and must be used as last resort they include: | Inner forearm, the wrist area above the thumb, and the back of the hand |
| If the medical assistant is able to palpate a small vein in the antecubital space it may be possible to obtain blood using | The butterfly method of venipuncture |
| Is obtained from a tube that does not contain an anticoagulant | Clotted blood |
| Is obtained from clotted blood by allowing the specimen to stand and then centrifuging it. Uses a tube that does not contain anticoagulant. | Serum |
| Is obtained using a tube that contains an anticoagulant. An anticoagulant is a substance that inhibits blood clotting is important to gently invert the tube back and forth 8 to 10 times after collection | Whole blood |
| Is obtained from whole blood that has been centrifuge. Uses a tube that contains an anticoagulant. | Plasma |
| This method is considered ideal for collecting blood from normal healthy antecubital veins that are adequate in size to withstand the pressure of the vacuum of the collection tube | Vacutainer method |
| A safety engineered needle used with the vacutainer method consists of | A double pointed stainless steel needle with a threaded hub near its center and a safety shield |
| The needle should not be used if the | Seal has been broken |
| Is longer and has a beveled point designed to facilitate entry into the skin and the vein | Anterior needle |
| Is shorter and it's purpose is to pierce the rubber stopper of the collection tube | Posterior needle |
| Has a rubber sleeve that functions as a valve which permits the collection of multiple blood specimens | Posterior needle |
| What gauge needle is used most often for a routine venipuncture? | 21 gauge |
| What gauge needle is recommended for children and adults with small veins for a venipuncture? | 22 gauge |
| Blood collection needles come in three lengths they are: | 1 in., 1.25 in., 1.5 in. |
| The length of the needle used is based on individual preference. Most medical assistants prefer the: | 1 or 1.25 inch needle for routine venipuncture |
| The large opening of the tube holder has a plastic extension known as the | Flange |
| Evacuated collection tubes consists of a sterile plastic or glass tube with either a | Hemogard closure or a conventional rubber stopper closure |
| A collection tube has a label affixed to it indicating the | Additive content, expiration date, and the tube capacity |
| Consists of a special rubber stopper with a plastic safety- engineered closure that overhangs the outside of the tube and works to prevent splattering of blood when the top is removed. | Hemogard closure |
| What color tube does not contain an anticoagulant and is used to obtain clotted blood or serum. Clotted blood is for blood banking. Serum is required for serologic test and blood chemistry test. | Red |
| These tubes are used to obtain serum. Do not contain anticoagulant however they do contain an additive known as a clot activator. Clot activator is a substance that makes the red blood cells clot more quickly to yield serum. Also known as SST tubes. | Gold or marbled red/gray (tiger top) |
| Is a tube that contains the anticoagulant EDTA and is used to obtain whole blood or plasma. The most common use is to collect a blood specimen for CBC. | Lavender |
| A tube that contains the anticoagulant sodium citrate and is used to obtain whole blood or plasma; the most common use is for the coagulation test such as prothrombin time | Light blue |
| A tube that contains an anticoagulant heparin and is used to collect a blood specimen to perform a blood gas determination or pH assay. | Green |
| Is a tube that contains sodium fluoride and potassium oxalate and is used to obtain whole blood or plasma; the most common use is to collect a blood specimen to perform a blood alcohol test, drug test, or an oral glucose tolerance test (OGTT) | Gray |
| Is a tube that contains either EDTA or no additive at all. This type of tube is made of a specifically refined glass and rubber stopper and is used for the detection of trace elements such as lead, zinc, arsenic, and copper. | Royal blue |
| Is a tube that contains plasma separator gel and lithium heparin and is used to obtain potassium determinations. | Light green or marbled green/gray |
| Is a tube that contains sodium polyanethol sulfonate (SPS) and is used for blood cultures and other tests that require sterile specimens. | Yellow |
| The order of draw for collection of multiple evacuated tubes is: | Yellow, Light blue, Red, Gold or Marbled red/gray, Light green or Marbled green/gray, Green, Lavender, Royal blue, Gray |
| How many times should a yellow tube be inverted? | 8 to 10 |
| How many times does a light blue tube need to be inverted? | 3 to 4 |
| How many times does a red tube need to be inverted? | Glass: no additive 0 Plastic: clot activator 5 |
| How many times does a gold or marbled red / gray tube need to be inverted? | 5 |
| How many times does a light green or marbled green / gray to need to be inverted? | 8 to 10 |
| How many times does a green tube need to be inverted? | 8 to 10 |
| How many times does a lavender tube need to be inverted? | 8 to 10 |
| How many times does a gray tube need to be inverted? | 8 to 10 |
| Premature loss of vacuum in the tubes can occur from the following: | Dropping the tube. Pushing the posture needle through the tube closure before puncturing the vein. Partially pulling the needle out of the vein after penetrating the patient's vein. |
| What happens if the collection tube is removed before the vacuum is exhausted? | A rush of air enters the tube damaging the red blood cells |
| One inversion consists of: | One complete turn of the wrist 180° and then back again |
| The butterfly method of venipuncture is also called the | Winged infusion method |
| What term is derived from the plastic "wings" located between the needle and the tubing of the winged infusion set | Butterfly |
| Is used to collect blood from patients who are difficult to stick by conventional methods because it provides better control when making a puncture and less pressure exerted on the vein wall from the collection tube | Butterfly method |
| The butterfly method is recommended for | Adults with small antecubital veins and children, who typically have small antecubital veins |
| The gauge of the butterfly needle used to collect a blood specimen ranges from | 21 gauge to 23 gauge |
| The length of a butterfly needle ranges from | 0.5 to 0.75 inch |
| For extremely small veins what butterfly needle gauge should be used to prevent rupture of the vein | 23 gauge |
| When a 23 gauge butterfly needle is used it is preferred to use | Smaller volume tubes (ex. 2 mL) because large collection tubes may put too much vacuum pressure on the vein causing it to collapse |
| Is attached to a posterior needle with a rubber sleeve and a plastic tube holder is screwed onto it | Luer adapter |
| At what angle does the butterfly needle go into the skin? | At a 15° angle and then when the vein has been entered decrease the angle to 5° |
| After decreasing the butterfly needle angle to 5° slowly thread the needle inside the vein and additional | 1/4 inch to seat the needle inside the vein |
| After two unsuccessful attempts at venipuncture the medical assistant should | Seek assistance in obtaining the blood specimen |
| Factors that result in failure to obtain blood after the needle has been inserted include: | Not inserting the needle far enough, preventing it from entering the vein; insertion of the needle too far, causing it to go through the vein; and the bevel opening becoming lodged against the wall of the vein. |
| Inappropriate puncture sites include: | Skin areas that are scarred, bruised, burned, or adjacent to areas of infection. Other sites to avoid are an arm with a cast applied or an arm on the side of a radical mastectomy. |
| To prevent a vein from rolling you should: | Apply firm pressure below and to the side of the vein to stabilize it as the needle is inserted |
| Veins are most likely to collapse on individuals who have | Small veins or veins with thin walls |
| If the needle comes out of the vein prematurely, pressure exerted by the tourniquet, blood may be forced out of the puncture site and immediate action is required to prevent a hematoma like: | Tourniquet should be removed at once, a gauze pad placed on the puncture site, and pressure applied until the bleeding has stopped |
| Is caused by blood leaking from the puncture site of the vein into the surrounding tissues resulting in a bruise | Hematoma |
| A hematoma can be caused by | A needle that is inserted too far and goes through the vein, a bevel opening that is partially in the vein and partially out of the vein, and significant pressure applied to the puncture site after removal of needle |
| The first sign of a hematoma is: | Sudden swelling around the puncture site |
| To prevent hemolysis of the specimen what guidelines should be followed: | Store the collection tubes at room temperature. Allow the alcohol to air dry completely. Use an appropriate gauge needle to collect the specimen. Practice good technique and collecting the specimen. Remove tourniquet within 1 minute. |
| Is caused by unpleasant physical or emotional stimuli, such as pain, fright, or the site of blood | Vasovagal syncope |
| Before fainting the patient usually experiences some warning signals such as | Sudden light-headedness, nausea, weakness, yawning, paleness, blurred vision, a feeling of warmth, and sweating followed by drooping eyelids, a weak rapid pulse, and finally unconsciousness |
| Fainting during or after venipuncture is more likely in the following individuals: | Patients having a venipuncture for the first time, young patients, thin patients, patients with a low diastolic or a high systolic blood pressure, patients with a history of fainting, nervous & apprehensive patient's who are very quiet or very talkative |
| Other factors that contribute to fainting and that should be avoided include: | Fatigue, lack of sleep, hunger, and environmental factors, such as a noisy, crowded, or overheated room |
| Because the amount of serum recovered is only a portion of the specimen, a blood specimen must be drawn that is | 2.5 times the amount required for the test |
| After the blood specimen is collected in the SST or red tube and has been allowed to stand for 30-45 mins. at room temp. and the blood cells have clotted the specimen is centrifuged for | 10 minutes to separate the serum from the blood cells |
| An SST tube is also known as a | gel barrier tube |
| The SST (serum seperator tube) is identified by a | gold or marbled red/gray closure |
| The SST (serum seperator tube) contains a: | thixotropic gel (serum seperator gel) |
| If a red-closure tube has been used to collect the specimen, the serum must be removed from the clot to prevent leaching of substances from the cell layer into the serum which affects the accuracy of test results. The serum is removed using | A pipet and placed in a separate transfer tube |
| Is unsuitable for labratory test because the results would be inaccurate and another blood specimen must be collected | Hemolyzed serum |
| A skin puncture is used to obtain a capillary blood specimen and is also called a | Capillary puncture |
| Examples of skin puncture test performed in the medical office include: | Hemoglobin, hematocrit, blood glucose, mononucleosis, and prothrombin time |
| A finger puncture should NEVER be performed on | Infants |
| The skin puncture on a adult's finger must not penetrate deeper than | 3.1 mm |
| The skin puncture on an infant (plantar surface of the heel) and children must not penetrate deeper than | 2.0 mm |
| The gauge of the lancet used to perform the skin puncture is based on the amount of | Blood specimen required |
| Lancet needle sizes range from | 18 gauge to 30 gauge |
| Where is a used lancet discarded | In a sharps container |
| Blood specimens can be collected in a small container known as a | Microcollection device |
| Consist of a small plastic tube with a removable blood collector tip. The tip is designed to collect capillary blood from the skin puncture, which results in a relatively large blood specimen | Microcollection tubes |
| Consist of a disposable glass or plastic tube. Depending on the size of the tube it can hold 5 to 75 uL of blood | Capillary tubes |
| The tubing of the butterfly setup contains how much air? | 0.3 to 0.5 mL |
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Diamond87