NCCT Phlebotomy

After selecting the appropriate location to collect a blood sample, how many inches above that location should the phlebotomist fasten the tourniquet?

3 to 4 inches Tourniquets are used to make it easier to locate veins by causing them to become distended and easier to palpate. This occurs because the tourniquet impedes venous blood flow right (i.e., below the application site) but does not impede arterial blood flow. Most phlebotomy experts recommend a tourniquet be applied approximately 3 to 4 inches above the site of blood collection for optimum palpation in venipuncture. Placing a tourniquet too far away will not impede blood flow sufficiently to help with palpation, but too close may cause hemoconcentration, possibly affecting the ratio of cellular components to plasma and laboratory test results.

Forceful shaking of blood in an evacuated collection tube will cause which of the following complications?

hemolysis Hemolysis is the breakdown/damage of blood cells and could end in an unusable specimen and costly re-draw for the patient. Hemostasis is when bleeding is stopped, hemoconcentration is the loss of plasma, and contamination is when something dirty causes the material to be unusable.

The appropriate needle gauge to use for most venipuncture collections is

21 The 21 gauge needle is long enough and thin enough to access most veins and the internal diameter (bore size) is wide enough to permit blood collection with little concern about mechanical hemolysis when using evacuated tubes. Butterfly collection sets (wing sets) typically use needles of a higher gauge, and blood donation centers typically use needles of a lower gauge. Remember, the higher the gauge, the smaller the bore (opening).

The medical assistant is educating the patient on fasting diet requirements prior to a glucose tolerance test. What is the minimum time frame the patient must remain NPO before the start of the test?

8-12 hours To ensure accuracy of the blood test results, the patient must remain NPO for 8-12 hours prior to the test. Gum chewing, eating mints, and/or smoking are not allowed. Sips of water may be permitted depending on the provider NPO policy.

Patient has a DVT in left arm and the patient is also on blood thinners, where would be the best site for drawing blood?

A patient with a deep vein thrombosis (DVT) in the left arm requires special precautions during a phlebotomy procedure. Blood thinners are a common treatment for DVT. The best site for collecting a blood sample would be the right arm, opposite the DVT. Once the draw is complete, pressure should be applied for 5 minutes since the patient is on blood thinners. A foot draw would not be recommended in this case.

What action should the medical assistant take to make a vein more prominent when attempting to select a venipuncture site?

Apply a warm compress to the area for 5 minutes The medical assistant should apply a warm compress to the area for 5 minutes. Warm moist heat promotes circulation and vasodilation and will help make the vein more visible. Tapping the arm or dangling the arm will not cause the vein to be as prominent as applying a warm compress. Applying firm pressure to the arm will occlude the blood flow and will not make the vein more prominent.

What is the proper way to identify a patient prior to performing a venipuncture?

Ask the patient to state his/her full name and DOB and compare to the chart. Before a venipuncture, the medical assistant should ask the patient to state his/her full name and DOB (comparing what is stated to what is written in the chart or on a wrist band patient identifier). This minimizes the risk for mis-identification errors because it cross-checks what the patient says against written documentation. This provides a verified identity so that all tubes collected will be associated with the correct patient (provided the medical assistant labels them properly).

What is the laboratory abbreviation for calcium?

Ca Ca is the scientific abbreviation for calcium. The laboratory uses scientific abbreviations from the Periodic Table of Elements. CA = cancer, carcinoma. Calorie = cal. CAL can indicate many things, but is not the general abbreviation for calcium.

Prior to any type of inpatient specimen collection, a phlebotomist must correctly verify their patient's identity by using which two-step procedure?

Check ID bracelet, and ask patient to verbally confirm their identity. The correct answer is to check the ID bracelet and ask the patient to verbally confirm his/her identity. Patients may not have foot bed charts or IV bags, and the goal is to select the BEST answer of all choices. If a patient has both an ID bracelet and can verify his/her own identity, it is ideal.

The phlebotomist needs to draw routine labs. The skin preparation for this procedure would be.

Cleanse the site by using a circular motion from center to periphery Phlebotomists cleanse the selected venipuncture site before routine lab draws. Cleansing is accomplished by moving the alcohol pad in a circular motion from the center to the periphery of the puncture site. The alcohol pad is sterile at first touch to the patient's skin and thereafter will contain surface bacteria from the skin. If a blood culture is ordered, disinfection is required before the collection; disinfection devices can vary among institutions, but often include an isopropyl pad and providone iodine swab and possibly the PREP method (70% isopropyl/10% acetone scrub and povidone iodine dispenser). Total sterilization of the skin is not possible.

The medical assistant is collecting a sample on a 2 year old outpatient by finger stick. Following the collection, the medical assistant holds firm pressure on the site until bleeding has stopped. How should the medical assistant proceed?

Do not bandage the site. If the child has shown evidence of wanting to touch everything in sight, the phlebotomist should not add a bandage to the list of things within his reach as a 2 year old could easily decide to put it in his mouth. Putting a smiley face on the bandage might make it even more enticing. A pressure dressing is unwarranted if firm pressure was held on the site until bleeding stopped. Bandages are not biohazards prior to being used, but only become so when in contact with blood.

Identify the CLSI recommended micro-collection order of draw for a BMP, CBC & Bilirubin.

EDTA, Heparin, Serum Separator The recommended Order of Draw for capillary blood collection is different from blood specimens drawn by venipuncture. CLSI recommends the following order of draw for skin puncture: Blood gases, EDTA tubes, Other additive tubes, then Serum tubes.

When performing a CBC on a six year old, the parent insists upon using an anesthetic at the venipuncture site. Which would be correct?

EMLA EMLA is the topical anesthetic of choice for pediatric venipuncture. The other anesthetic choices in this question are not typically available to or used by phlebotomists. EMLA Cream (lidocaine 2.5% and prilocaine 2.5%) is an emulsion, with a mixture of lidocaine and prilocaine.

The physician orders a sedimentation rate for a patient recovering from an infection. This is indicated on the lab requisition as which of the following?

ESR The Erythrocyte Sedimentation Rate (ESR) is a common test to detect inflammation by measuring the rate at which red blood cells settle to the bottom of a tall, thin tube. Since inflammation can cause cells to clump, these clumps are heavier than single cells and settle more quickly. The test measures the distance settled in one hour. This test is most useful in combination with other more specific laboratory tests. EBV = Epstein Barr Virus (causes a number of diseases, including infectious mononucleosis) CRP = C-Reactive Protein ( appears with inflammation in the body) INR = International Normalized Ratio (a measure of coagulation)

Since special precautions are needed for patients with Vascular Access Devices, which of the following devices are contraindicated for any type of blood draws?

Fistula The AV fistula requires the surgical connection of a vein and artery, typically in the forearm. It is predominately used for patients in renal failure who may need long term dialysis. To avoid any complications, blood draws are contraindicated. Central venous access devices/catheters are small, flexible tubes placed in large veins for people who require frequent access to the bloodstream. They are more easily created than the arteriovenous fistula, and there are more available locations for placement.

Which of the following actions should the medical assistant take to prevent hemolysis of a blood specimen in an EDTA tube?

Gently invert the tube after collecting the specimen. Since an EDTA tube contains anticoagulant, it is important to immediately mix the blood as soon as it is collected to ensure that it doesn't clot. The medical assistant should gently invert the tube after collecting the specimen to maintain specimen integrity and prevent rupture of RBC's in the sample. The smaller gauged needles would introduce a higher likelihood of hemolysis, not prevent it. Refrigerated storage would not necessarily prevent immediate hemolysis (but would slow down the breakdown of RBCs that would cause hemolysis over time). The tube should be gently mixed immediately after collection and can be processed and run as soon as needed (it does not need to stand for 20 minutes). Previous Question Next Question

Which of the following tests is drawn in an EDTA tube for the hematology department of the laboratory?

HGB HGB is an abbreviation for Hemoglobin, typically measured as part of a Complete Blood Count and collected in an evacuated tube containing Ethylenediaminetetraacetic acid (EDTA). Hemoglobin is a protein inside red blood cells that carries oxygen to organs and tissues, while also transporting carbon dioxide back to the lungs. BMP = basic metabolic panel (common screening panel with tests for renal function, electrolyte balance, glucose, and more) HCG = human chorionic gonadotropin (pregnancy test) PTT = partial thromboplastin time (a common test for coagulation abnormalities or to monitor patients on heparin therapy)

A patient's past history indicates episodes of syncope. Which of the following would be the best course of action the phlebotomist would perform to prevent complications of syncope?

Have the patient lie down on a hospital bed or exam table. Syncope is a temporary loss of consciousness and posture, commonly referred to as fainting, which is usually related to insufficient blood flow to the brain for any number of reasons. If a patient has a history of syncope episodes, it would be advisable to position the patient to avoid the possibility of injury and to enable ease of oxygenated blood flow to the brain. The angle of the needle has no bearing upon the possibility of syncope and wouldn't prevent injury in case of a fall. Holding pressure over the venipuncture site only prevents bleeding. Placing an object in a patient's mouth to prevent biting the tongue is not advised in cases of either seizure or syncope.

Which of the following characteristics applies to veins

Have valves to prevent backflow of blood Veins have valves which maintain the unidirectional flow of blood, even against gravity. Veins are also the blood vessels which carry the blood from peripheral tissues towards heart. They carry the deoxygenated blood, which is bluish in color and for the same reason veins appear blue.

The medical assistant is instructed to perform a capillary stick for newborn screening. What collection devices should the medical assistant use?

Heel stick lancet The heel stick lancet (e.g., Tenderfoot) is required for infants. If a heelstick in an infant is being performed, the phlebotomist should apply a warming device for approximately 3-5 minutes to the heel to increase blood flow to the area, which will facilitate the collection of the capillary specimen. The bones of the distal phalanx (located in the thickest part of the finger) may be injured or damaged by a traditional finger stick lancet puncture.

After a phlebotomy draw, the phlebotomist realizes the tourniquet was on the patient's arm for an extensive length of time. Which of these is the most common complication?

Hemoconcentration Hemoconcentration is decrease in the volume of plasma in relation to the number of red blood cells. Prolonged tourniquet use impedes circulation and will cause this to happen, but will likely not cause hemolysis or a hematoma. Hematocrit is a measure of the volume of red blood cells in a whole blood sample, and is not a physiological complication at all.

The medical assistant completes a venipuncture in the antecubital area without complications. Pressure is placed on the site following the collection. The patient is still bleeding after five minutes of continuous pressure by the medical assistant and there is bruising at the site. The medical assistant asks the patient if she is on anticoagulants. The patient indicates that she is, and states that this is normal for her. How should the medical assistant proceed?

Hold direct pressure until bleeding stops, apply a bandage, and notify nurse. It is the responsibility of the phlebotomist to ensure bleeding has stopped before leaving the patient. In addition, since bruising had occurred at the site, nursing staff will want to know the source for documentation and follow up purposes.

During a venipuncture the patient has excessive bleeding and then states she forgot to mention her anticoagulant (Coumadin) therapy. What should the medical assistant do?

Hold pressure on the site for a minimum of five full minutes until bleeding stops. A patient on Coumadin therapy will have thin blood and the Medical Assistant will have to hold at least 5 minutes of continuous pressure to be sure a clot has formed at the puncture site. Coumadin is an anticoagulant, it thins the blood, so it takes longer to clot.

A physician asked you to draw a INR on Mr. Jones which tube and additive would you choose

Light Blue, Sodium Citrate An INR test refers to an International Normalized Ratio, which provides a standardized method of reporting prothrombin time results by comparing the ratio of the patient prothrombin time to the control prothrombin time. This, in turn, helps to standardize the method of reporting the effects of oral anticoagulant therapy on blood clotting. It uses the light blue tube with sodium citrate as it would for a regular prothrombin time (Pro Time) test.

The laboratory requisition indicates that you are to collect a venous blood specimen for hematology CBC testing, serum chemistry testing, and coagulation studies. What is the proper order of collection for these tubes?

Light blue, red, lavender Light blue (coagulation studies), red (serum chemistry), then lavender (hematology CBC) tubes follows CLSI established order of draw.

A phlebotomist is staffing the outpatient clinic at a remote site. There is a centrifuge at the site, but it is not functional. The courier will be arriving to pick-up all samples collected at 1300, and will deliver to the testing laboratory at 1500. A patient arrives at 1200 with orders for Complete Blood Count, Prothrombin Time, and Basic Metabolic Panel. Which tubes should the phlebotomist use for blood collection?

Of the answer options provided, the best answer would accommodate testing accordingly: Complete Blood Count (CBC) = lavender top tube (EDTA) Prothrombin Time (PT)/INR = light blue top tube (sodium citrate) Basic Metabolic Panel (BMP) = green top tube (heparin); since the centrifuge is not functional and there is a bit of a delay between draw time and courier pickup/delivery to the laboratory, a gray top tube would best preserve the glucose value within the BMP.

Which of the following tests monitor anticoagulation therapy?

PT and PTT PT and PTT are coagulation tests (collected in blue top tubes). They are routinely collected to monitor a patient's anticoagulant drug therapy (to make sure that the dose the patient is taking provides the proper effect, but does not dangerously over-anticoagulate and introduce a critical risk of bleeding). In short, these tests monitor a patient's blood clotting time. T3 and T4 are thyroid tests. Hgb and Hct reflect the amount of hemoglobin in the red blood cells and the number of red blood cells per volume of whole blood (hematocrit). ABO and Rh are blood typing tests that determine a patient's blood group.

Name the two most used patient identifiers.

Patient's name/date of birth Name and DOB are most often used as positive patient identifiers as they are easily documented and work for inpatients or outpatients. Bed numbers should never be used as identifiers for inpatients or outpatients, nor should physician name associations. Medical record numbers are valuable for inpatients, with name and DOB being used most often.

A phlebotomist inserts a needle into a patient's vein and notices there is no blood flow into the tube. The needle is positioned against the wall of the vein. How should the phlebotomist proceed?

Relax the needle's angle slightly, and insert new tube If the needle is believed to be positioned against the vein wall, sometimes relaxing the needle's angle slightly will bring blood into the blood collection tube. In case the tube's vacuum was compromised, using a new tube should provide blood flow. Retracting the needle might pull it out of the vein entirely. Starting over subjects the patient to the discomfort of another needle stick, and inserting the needle deeper may cause the needle to move through the vein entirely.

When performing a venipuncture, sudden swelling is observed at the insertion site. What action should the medical assistant take?

Release the tourniquet, remove the needle, and immediately apply pressure at the site. The medical assistant should release the tourniquet, remove the needle, and immediately apply pressure to the site. The sudden swelling is an indication that the needle has traumatized or penetrated through both sides of the vein. This is also referred to as a "blown" vein. Though always a possibility, this is not a normal occurrence for a venipuncture. Pressure should be held directly on the site (not above it) because it is important to stop the bleeding.

During a blood draw, a patient begins complaining of discomfort and tingling, at which time the phlebotomist notices bruising and discoloration at the site. How should the phlebotomist proceed?

Release the tourniquet, withdraw the needle, and apply pressure. The correct response is to release the tourniquet, withdraw the needle, and apply pressure to avoid any further damage or pain at the venipuncture site. The tourniquet MUST be released before the needle is withdrawn. The application of pressure by the phlebotomist is meant to stop any bleeding. The use of ice and bending of the arm are not typically recommended after any phlebotomy procedures.

After the phlebotomist puts on latex gloves and ties a non-latex tourniquet on the patient's arm, the patient indicates that he is highly allergic to latex. What is the phlebotomist's best course of action?

Remove the tourniquet, wash hands, change to non-latex gloves and use a new tourniquet. The key here is not to expose the patient to latex. The phlebotomist should remove the tourniquet that is on the patient (taking care not to touch the patient with anything latex). Washing the hands removes any residual latex that may be on the skin. Non-latex gloves should then be put on, and a new non-latex tourniquet should be used.

Using the guidelines for any method of venipuncture, what action should the medical assistant perform directly after confirming patient identity?

Review the requirements for collecting and handling the blood specimen as ordered by the physician To ensure accuracy and quality, it is important to anticipate your needs before beginning the actual venipuncture (i.e. tube color/size, minimum acceptable blood volume, whether or not the specimen needs to be placed on ice). Therefore, the medical assistant would identify the patient, then review the requirements for collecting and handling the blood specimen as ordered by the physician. Next, assemble the appropriate equipment and select the proper evacuated tubes for test to be performed. Then, apply the tourniquet and thoroughly palpate the selected vein. Finally, position the patient's arm and cleanse the site with an antiseptic wipe, then proceed with the venipuncture protocol.

Which of the listed tubes can contain ethylenediamine tetraacetic acid?

Royal blue Royal blue blood Collection tubes may be purchased with EDTA, sodium heparin, or no additive at all. They are used for trace element testing via plasma or whole blood. They can also be used for toxicology and nutritional studies. The most common tubes that contain EDTA are lavender top/light pink tubes.

The phlebotomist is drawing plain red, lavender, and blue top tubes. Upon completion of the blood draw, the phlebomist noticed that an order that requires a SST has been missed. What would be the next action?

Share the plain red top specimen for the SST test. A plain red tube and an SST tube both will yield serum once clotted and centrifuged. Therefore, it is possible to share the plain red top specimen for the SST test. There is no need to re-stick the patient. The lavender and blue top tubes both contain anticoagulant, thus they produce plasma (not serum) when centrifuged. They would not be good substitutes for an SST specimen.

A phlebotomist has received a requisition to collect a blood culture. Using a butterfly, three milliliters of blood is collected. Into which of the following bottles is the proper dispensation of the specimen?

Since the phlebotomist was only able to obtain three milliliters of blood, place all three mLs in the aerobic bottle. The aerobic bottle would be the first bottle to innoculate if there is limited sample. It is not advisable to split the innoculation of 3 total mLs into both bottles since it would not adequately innoculate either bottle. The fact that a butterfly was used in this instance indicates that the patient was probably a hard stick, thus attempting a recollection is not the first course of action here. The first course of action is to best utilize the sample that was collected by dispensing all of it into the aerobic bottle.

When performing a skin puncture on an infant what is the preferred site?

The plantar surface of the heel The heel of an infant is the recommended skin puncture site. Avoid puncturing the bone by targeting the plantar surface. Draw an imaginary line starting in the middle of the big toe to the back of the heel. Then draw another imaginary line between the small toes to the back of the heel. The proper collection sites will be the fleshy portions outside those lines and below where the arch meets the heel. The anteromedial aspect, lateral surfaces and plantar curvature do not provide good flesh for a proper collection.

The medical assistant is collecting four tubes of blood on a patient who begins wheezing. She asks the patient if he is okay, he states that he has asthma. The medical assistant is in the process of switching to the fourth tube when the patient faints in the phlebotomy chair. Which of the following steps should the medical assistant take?

Stop the collection, apply pressure to site, call for help, and assist the patient. When a patient faints, the most important consideration is patient safety. Since the patient was in an outpatient phlebotomy chair, he had some protection from falling, giving the phlebotomist time to stop the collection and apply pressure to the site to avoid bleeding. Since it was important to remain with the patient, the phlebotomist would call for help and tend to the patient's needs. Ammonia salts would not be advisable in a wheezing patient, as they might aggravate any type of existing lung condition.

A medical assistant has active symptoms of the common cold. Under which of the following conditions may he perform venipuncture?

The medical assistant may perform venipuncture provided he is wearing a mask and afebrile. It is not uncommon for people to be able to work with the common cold. However, it is important for medical personnel to use good judgment and not transmit diseases to their patients. Medical personnel should take precautions and handle patient contact in a responsible manner. They should not have patient contact if they are febrile, since that is when colds are highly contagious. In this instance, the medical assistant may perform venipuncture provided he/she is wearing a mask and afebrile. The medical assistant should wear the mask to keep from transmitting the cold via coughing or sneezing on a patient.

After centrifuging a blood specimen, the medical assistant notes the serum has a reddish appearance. Which of the following has occurred?

The specimen is hemolyzed. Normal serum should be amber-colored. If it's reddish in appearance, the specimen is hemolyzed. The reddish color is caused by broken red blood cells, not neutrophils (which are white blood cells). The buffy coat is the layer of white blood cells and platelets that forms in whole blood between the plasma and the red blood cells. This question eludes to serum, which is the liquid layer of clotted blood (the white blood cells/platelets would be contained within the clot).

Which of the following statements best describes the reason antecubital veins are most desirable to use when performing venipuncture?

The tissue surrounding these veins is less sensitive, making the procedure less painful. Of the three veins in the antecubital area acceptable for venipuncture, the median cubital vein (in the middle) is the vein of choice for four reasons: 1) it's more stationary; 2) puncturing it is less painful to the patient; 3) it's usually closer to the surface of the skin; and 4) it isn't nestled among nerves or arteries.

What action is appropriate for the medical assistant to take if an evacuated tube does not even begin to fill during a specimen draw?

Try another evacuated tube prior to withdrawing from the vein In this instance, it is important to maintain a closed system and avoid re-sticking the patient if possible. Therefore, the medical assistant should try another evacuated tube prior to withdrawing from the vein (it is possible that the vacuum was compromised on the first tube for whatever reason). Though it may eventually be necessary, it is not the first choice to terminate the stick and reattempt to complete collection. Rotating the tube may restore vacuum pressure within a vein to restart blood flow, but this question described a tube that never began to fill in the first place. Inverting the tube would not do anything to help in this instance.

Capillary blood specimens are typically collected on patients that

are extremely obese. Capillary blood samples are advisable on patients when veins are not palpable, which includes patients who are morbidly obese, among others. A phlebotomist should never just "hope for the best" if a vein cannot be located.

When a complete metabolic profile (CMP) and complete blood count (CBC) are ordered at the same time, why should the CMP be drawn first?

Tubes without additives should be drawn before tubes with additives. A blood specimen will naturally clot (yielding a serum component) when collected in a tube without an additive to anticoagulate it and keep it whole blood (which has a plasma component). With the exception of blood cultures and coagulation tests (e.g. PT, PTT), serum tubes (for CMP, Lytes, etc.) should be collected before tubes with additives (e.g. lavender top for CBC) to avoid contamination of the serum tube with the additive (can cause erroneous results in the serum tube). CLSI lists the order of draw as follows: 1. Blood cultures 2. Coagulation tube (e.g. blue closure) 3. Serum tube with or without clot activator, with or without gel (e.g. red closure) 4. Heparin tube with or without gel plasma separator (e.g. green closure) 5. EDTA tube with or without gel separator (e.g. lavender closure, pearl closure) 6. Glycolytic inhibitor (e.g. gray closure)

A phlebotomist is asked to collect a CBC, PT and Chem 7 on a patient that requires a hand stick with a butterfly needle into evacuated tubes. The correct order of draw for this collection would be

Two Light Blue Top Tubes, Green Top Tube, Lavender Top Tube The correct order of draw would be: two light blue top tubes (one waste and one for PT which is a coagulation test), green top tube (for the Chem 7), and the lavender top tube (for the CBC).

After several minutes of searching the medical assistant can only palpate a small vein. The patient is prepared and the venipuncture is performed. The blood is filling the tube, but slows and then stops even though the patient and medical assistant remained still. What actions should the medical assistant take?

Use a smaller tube because the vein has collapsed. Since blood was once filling the tube, the needle was once in the vein. Since the phlebotomist knew this was a small vein at palpation, the fragility of the vein may have caused the vein to collapse if the vacuum of a regular size collection tube was too strong. Putting a smaller tube on the multi-sample needle would decrease the force of the vacuum pulling blood from the vein. If blood flowed easily again, problem is solved! Presuming the phlebotomist had a steady hand during the draw, the other causes could be ruled out. Since blood filled the tube normally for a time and slowed to a stop, there is no reason to believe the needle had been moved. And if the bevel was still in the vein at all, blood would still be able to trickle into the tube.

After a patient's skin is punctured to obtain a blood glucose level, what should be the phlebotomist's next step?

Use a sterile gauze pad to remove the first drop. It's important to wipe off the first drop of blood in any capillary collection, as this drop may include sufficient tissue fluid to influence test results. Using a sterile gauze pad helps to prevent infection without inhibiting blood flow. Using an alcohol pad might affect test results and is likely to cause discomfort. Squeezing the fingertip might increase the dilution of the sample with tissue fluid.

Filling evacuated tubes to the indicated level results in the correct ratio of

additive to blood Blood collection tubes are medical devices and manufacturers' directions for use must be followed as for any other medical devices. This is particularly crucial with respect to any stated minimum fill line for tubes with additives. If too little blood is drawn in a tube with an additive, the ratio of additive to blood is higher than expected. Insufficient sample volumes produce "relatively" elevated levels of the additives in the sample collected. There is simply too much additive for the amount of blood in the tube. Here are just a few examples of problems: Relatively elevated levels of EDTA (which binds calcium to prevent clotting) can bind too much calcium and begin binding other elements in the blood, which can affect several laboratory tests. Too much heparin per blood volume can produce negative anion gaps, slow antigen-antibody reaction rates, falsely low albumin levels, and significantly higher CK (creatinine kinase) levels.

When performing a venipuncture on an infant, the amount of blood taken from the infant should be monitored to avoid

anemia The removal of just 10 mL of blood from an infant can result in a 10% loss of total blood volume and lead to iatrogenic anemia caused by blood collection. This is most serious in the first week of life. For this reason, the amount of collected blood must be carefully logged over time. Septicemia is not related to the amount of blood, but to the introduction of microorganisms into the bloodstream. Polycythemia (an abnormal proliferation of blood cells) is a hereditary condition. Venous thrombosis refers to blood clots in the veins, which may occur with indwelling catheterization but are typically not connected to venipuncture.

Which of the following types of additives is present in an EDTA tube?

anticoagulant An EDTA tube contains the anticoagulant sodium ethylenediamine tetra-acetic acid, which prevents clotting. Red top tubes can be plain or have gel separators. Plastic red top tubes can contain a clot activator to expedite the clotting process. Common blood collection tubes are already sterile, thus don't contain antimicrobial additives.

EDTA is an

anticoagulant. Ethylenediaminetetraacetic acid (EDTA) is a chelating agent in lavender top blood collection tubes that binds calcium, an essential component for human blood coagulation. It is valuable as an additive as it prevents whole blood from clotting in vitro (i.e., inside the tubes), which is preferential for a variety of medical laboratory tests.

An infant is brought to the clinic for a CBC. After performing a heelstick, not enough blood is collected to perform the test. What action should the medical assistant take?

apply a warm compress. The heat from a warm compress will encourage capillary vasodilation resulting in increased blood flow. Warming helps make blood collection easier and faster. Warm the heel for 3-5 minutes, which allows sufficient time for the capillaries to dilate. Squeezing can create discomfort and will not necessarily get more blood (it may also extract serous fluid that would dilute an already small amount of blood sample). The only content to be added to a microtainer collection tube is blood (adding a diluent would skew the results). A cold compress would decrease blood flow, which is the opposite desired effect.

To help prevent a hematoma at the site after drawing blood, which of the following actions does the medical assistant take?

apply direct pressure with cotton gauze To promote clotting and help prevent the leakage of blood outside of the vein (hematoma or bruise), the medical assistant should apply direct pressure with cotton gauze. Asking the patient to make a fist, cleaning the site with an alcohol prep, or having the patient bend the elbow will not prevent a hematoma from forming.

An entry level medical assistant goes to collect blood from a 70-year-old woman with diabetes who had a mastectomy of the left breast. The medical assistant notices a PICC line in the patient's right arm. For this specimen collection, the medical assistant should

ask a nurse to collect the specimen. This scenario is a scope of practice example. The medical assistant should ask a nurse to draw the sample. PICC line draws are outside an entry level MA's scope of practice. It should be noted that a facility may offer special training for PICC line draws, but specific training must be completed and competency assessed before any personnel collect such specimens. Performing a venipuncture in the left arm is not an option because the patient's left breast has been removed (it is not advisable to draw blood from an arm on the same side of a mastectomy). It is easier on the patient to have a nurse collect the specimen from the PICC line instead of enduring a venipuncture in an ankle.

At what time should a test tube be labeled with the patient's identification?

before leaving the patient's room, after drawing the blood Three crucial identification steps in phlebotomy must be performed in this sequence without interruption—(1) positively identifying the patient, (2) collecting the patient's blood into tubes, and (3) labeling the tubes immediately afterward. Any change in this sequence or any significant interruption between steps has been linked to significantly increased chances for error.

Which of the following specimens is most susceptible to cross contamination and should always be drawn first?

blood culture Since blood cultures test for sepsis (infection in the blood stream), the skin should be specially prepared to avoid contaminating the specimen during the collection process with normal skin bacteria. The exact preparation protocol may vary slightly among services, but most phlebotomy procedures will either use an iodine solution, ChloraPrep, or equivalent chlorhexidine-based skin antisepsis solutions. When blood cultures are ordered along with other laboratory testing, collect the blood cultures first. The regular alcohol pre-draw prep is sufficient for the CBC, cholesterol, and hematocrit (HCT can be ordered separately, but is included within a CBC).

What is an appropriate alternative to using a rubber tourniquet when attempting a venipuncture on a known patient who is difficult to obtain a sample from?

blood pressure cuff The only acceptable choice among the listed options is the blood pressure cuff. Occlusion pressure may be adjusted as needed as an alternative to ensure circulation. In compliance with CLSI (Clinical and Laboratory Standards Institute) standards, the blood pressure cuff can provide uniform constriction, as long as the phlebotomist doesn't inflate the cuff beyond 40 mm of mercury.

The physician has ordered a prothrombin time (PT) and complete blood count (CBC) for an adult patient with a diagnosis of thrombophlebitis. The medical assistant should collect the evacuated tubes in which of the following orders?

blue, lavender In the past, there was concern that the first blood collected into a tube or syringe was contaminated with tissue thromboplastin resulting from the entry of the needle into the skin. The presence of tissue thromboplastin in a blue top tube could alter the results of the routine coagulation tests, protime (PT) and activated partial thromboplastin (aPTT). Therefore, it was necessary to collect a small quantity of blood in another tube to assure that no tissue thromboplastin would contaminate the blue top tube. Research now indicates that the amount of tissue thromboplastin generated from a venipuncture today is minimal and will not affect the results of PT and aPTT testing. However, studies have not been performed for other coagulation tests so a discard tube should be filled with a small volume of blood prior to collecting blood into a blue top tube. NOTE: The "no discard tube needed" policy applies only when using a routine venipuncture with needle/tube holder or needle/syringe. A lavender (EDTA) tube is the appropriate tube to collect for a CBC test. CLSI (Clinical and Laboratory Standards Institute) lists the order of draw as follows: 1. Blood culture tube 2. Coagulation tube (eg, blue closure) 3. Serum tube with or without clot activator, with or without gel (eg, red closure) 4. Heparin tube with or without gel plasma separator (eg, green closure) 5. EDTA tube with or without gel separator.

While performing a venipuncture in the antecubital space, the patient verbalizes an extreme amount of pain and the blood in the collection tube is noted to be bright red. What site is most likely to have been inadvertently punctured?

brachial artery The brachial artery is most likely punctured, because it is a large artery and the bright red bleeding and fast, pulsating movement indicates arterial blood flow and not venous. The brachial artery runs in the antecubital space, and would cause a lot of pain if it was punctured. The medical assistant should apply pressure to the site for at least 5 minutes to ensure that clotting occurs.

A CMP is ordered for an older adult patient whose veins continue to collapse despite drinking water. Which of the following is the best collection method for this patient?

butterfly needle A butterfly is a smaller gauge needle device and is used for smaller veins, including fragile veins on all patients, elderly adults and small children. Other phlebotomy systems use larger gauge needles. The vacuum pressure in an evacuated tube system would collapse the vein. A needle and syringe would also have a tendency to collapse the vein (when the plunger of the syringe is pulled back). A capillary collection would be the last resort if all other collection methods failed. The butterfly is the best initial choice in this case.

A 2 week old infant has been brought to the lab for a repeat PKU/neonatal screening. What collection procedure is appropriate to collect the specimens?

capillary using heel puncture lancet PKU is a neonatal screening test collected on a blot card. The recommended method of blood collection on infants less than a year old is via capillary (thus eliminating the venipuncture choices). A capillary collection using heel puncture lancet would be the correct choice in this situation. The heel puncture lancet would go the proper depth on an infant (there are even different sizes of lancets available for premature vs. term infants).

When performing a fingerstick on a patient, the phlebotomist must pay close attention to the extremity that has been compromised by

circulation, swelling, and infection. When performing fingersticks, dry skin and bug bites would not cause problems in collection or recovery from collection. Thus, the only reasonable answer is circulation, swelling, and infection. If there is little circulation, blood flow may be greatly diminished. If the finger is swollen or appears infected, the phlebotomist risks further damage and pain to the patient.

The medical assistant collects blood for a test that requires a blood smear. What is the terminology that would indicate that the sample clumped (therefore requiring a redraw)?

coagulation Coagulation is a term that describes how blood clots (changes from a liquid to a clump or solid). Sometimes if the person performing a phlebotomy procedure fails to adequately mix the blood within a tube, the anticoagulant does not fully work and the sample will have clumps/clots. Thrombocytosis describes a disorder that occurs when the body produces too many thrombocytes (a.k.a. platelets). Hemolysis is a term used to indicate destruction of red blood cells. Thrombosis indicates the clotting of blood within a blood vessel (not a test tube).

While performing a venipuncture using an evacuated tube, a small amount of blood enters the tube and then stops. What condition is likely to lead to this?

collapsing vein When blood ceases to flow during the venipuncture process, the likely culprit is a collapsing vein. The walls of the vein lose tension, stopping blood flow. The sclerosed (scarred) vein would have been a tough stick, and blood flow likely would not have started. If a vein rolls, the needle generally misses the vein, resulting in no initial blood flow. A hematoma could form if the needle slips through the vein or if the bevel is only partially in the vein.

A medical assistant needs to draw a bilirubin on a jaundiced infant. The medical assistant should

collect the specimen in an amber tube to protect from light. Bilirubin is a photo-sensitive analyte (can degrade by as much as 50% with an hour of light exposure). A specimen submitted for bilirubin testing should be collected in an amber tube which will protect it from light (a regular tube wrapped in aluminum foil could also be acceptable). It is not necessary to keep the specimen warm with a heel warmer, nor is it necessary to chill the specimen to slow metabolism and stabilize the specimen. As long as the specimen is properly collected, protected from light, and handled according to normal serum protocol, it can be run as routine, thus Stat analysis is not necessary.

After a phlebotomist has successfully followed all the steps for blood collection, the patient informs the phlebotomist that he tends to bleed longer than the average person. What would be the next course of action for the phlebotomist?

confirm hemostasis and apply paper tape A proper phlebotomy procedure includes confirmation of hemostasis, regardless of whether or not a patient bleeds longer than normal. This definitely applies to this case when a patient admits a tendency to bleed longer than the average person.

After performing a venipuncture on a patient the medical assistant notices the patient is bending his elbow to hold the gauze in place. This action is contraindicated because bending the elbow is likely to

create a hematoma. If adequate pressure is not applied following a venipuncture, a hematoma can form via the transfer of blood from the vein into the surrounding tissue. Proper procedure would be to keep the arm straight and apply direct pressure until bleeding stops.

When collecting specimens for alanine aminotransferase (ALT) or aspartate aminotransferase (AST), avoid gray-topped sodium fluoride tubes because the anticoagulant

destroys many enzymes. The sodium fluoride in gray-topped tubes can destroy many enzymes. Since ALT and AST are enzyme tests, sodium fluoride should be avoided.

Venipuncture on the foot is performed in what location?

dorsal pedis

What artery provides direct blood flow to the foot?

dorsalis pedis The dorsalis pedis artery is located on the upper surface (dorsal region) of the foot, and provides direct blood flow to the foot. The popliteal artery is located behind the knee, the brachial artery is in the arm, and the femoral artery is in the thigh.

The medical assistant is asked to draw blood from a patient with an I.V. whose opposite, left arm is inaccessible. Drawing blood from which of the following sites would be appropriate without a physician's approval?

draw from the right arm distal to the I.V. site Collecting blood distal to the I.V. site prevents contamination of the sample by the intravenous solution. Medical assistants are not permitted to collect samples from an I.V. line and may not draw from an ankle vein without physician's approval.

What additive protects serum from interacting with red blood cells after a specimen has been centrifuged?

gel separators Gel separators create a barrier between the serum and formed elements of the blood. Prolonged contact of serum with formed elements can lead to pre-analytical variations in certain tests (such as serum glucose levels). Tubes with clot activators, such as thrombin, actually expedite the clotting process. Anticoagulant tubes keep the blood from clotting, yielding plasma instead of serum. Sulfosalicylic acid is used in urine testing to precipitate proteins.

A test tube with which of the following colored stoppers has a glycolytic inhibitor?

gray A gray top blood collection tube contains powdered sodium fluoride and/or potassium oxalate, which will inhibit glycolysis. Glycolysis involves the breakdown of sugar to produce energy. As an example, gray top tubes are used to collect blood samples for glucose tolerance tests because if any glucose present in the patient's blood would need to be preserved until tested; if the glucose were allowed to be broken down during processing (i.e., by the cells that metabolize it), the laboratory tests would not be able to measure the full amount present in the patient at the time of collection. The glucose value would be lower in vitro (in the lab) than in vivo (in the body of the patient).

What evacuated tube should the medical assistant select for collection of electrolytes?

green-top A green top tube contains heparin. Green tops are used for collection of heparinized plasma or whole blood for special tests. Note: After the tube has been filled with blood, the tube is inverted several times to prevent coagulation. Note: Green top tubes can contain ammonium, lithium, and sodium in addition to the heparin. In this instance, lithium heparin would be the green-top of choice (and sodium heparin would NOT be used for an electrolyte test). Electrolytes can also be collected in a red-top tube.

The physician orders a hemoglobin level to be checked on a 2-month-old patient. What site should the medical assistant use to obtain the specimen?

heel of the foot The heel of the foot is the recommended site to obtain a capillary sample on infants less than one year. The lateral (outside) or medial (inside) planter surface of the heel should be used for heel stick puncture. Never puncture other areas on the heel, as injury and /or nerve damage can occur.

While performing a venipuncture, the medical assistant removes the filled tubes, but forgets to remove the tourniquet prior to needle withdrawal. What is the most likely result?

hematoma A hematoma is a large painful bruise at the puncture site, caused or created by blood seeping into the surrounding tissues, one of the causes is the delay in tourniquet release and pulling the vacuum tube out. Since the tourniquet is causing the veins to bulge this will prevent quick clotting, and cause bruising. Syncope is fainting; hemoconcentration is when the concentration of blood cells are increased. Hemolysis specimens indicate the destruction of red blood cells after drawing the specimen, or during the procedure.

A phlebotomist has received a requisition for a PT/aPTT to evaluate the patient for Von Willebrand's disease. Because of the patient's potential diagnosis, the phlebotomist should be sure to

hold pressure on the draw site until bleeding has stopped. Von Willebrand disease is an inherited condition that can cause extended or excessive bleeding. Those affected have deficient amounts or impaired von Willebrand factor, a protein important to the clotting process. Thus, the phlebotomist must hold steady pressure on the venipuncture site until all bleeding has stopped. The collection site does not need confirmation from anyone, as the disease would not affect site selection. Edema is not a problem, and use of a blood pressure cuff could force more bleeding if applied after the draw.

What is the first step in performing a venipuncture?

identify the patient To prevent error and maintain a culture of safety, at least 2 identifiers (ex. full name and date of birth) must be verified prior to performing a procedure.

What should be avoided as a form of patient identification?

insurance number An insurance number is not a common means of positive patient identification (entire families can share the same insurance policy number). Patients must be positively identified for medical services, whether they have insurance or not. Insurance information is necessary for billing purposes. The only true unique identifier listed among these choices is the social security number. Patient name and date of birth are also commonly used to confirm identification.

Which of the following tubes should the medical assistant select in collecting a blood sample for a Complete Blood Count (CBC)?

lavender top, ethylenediaminetetraacetic acid additive A CBC is performed on a whole blood sample. It should be collected in a lavender top tube containing ethylenediaminetetraacetic acid additive as an anticoagulant. Blue top tubes contain sodium citrate anticoagulant and are commonly used for coagulation studies (PT, PTT, etc.). Green top lithium heparin tubes are commonly collected for chemistry tests that can utilize plasma. Specimens collected in red top tubes containing no additive will clot and form serum (commonly used for chemistry and serology testing requiring serum).

The physician orders a prothrombin time. Which of the following tubes should be used to collect the specimen?

light blue A light blue top tube contains sodium citrate to prevent blood from clotting. This tube contains sodium citrate as an anticoagulant and is used when blood is drawn for coagulation studies. Note: It is imperative that the tube be completely filled. The ratio of blood to anticoagulant is critical for valid prothrombin time results. Immediately after the draw, the tube needs to be inverted 6 to 10 times to activate the anticoagulant.

Which of the following evacuated tubes should the medical assistant draw first?

light blue top CLSI lists the order of draw as follows: 1. Blood cultures 2. Coagulation tube (e.g. blue closure) 3. Serum tube with or without clot activator, with or without gel (e.g. red closure, gold shield,etc.) 4. Heparin tube with or without gel plasma separator (e.g. green closure) 5. EDTA tube with or without gel separator (e.g. lavender closure, pearl closure) 6. Glycolytic inhibitor (e.g. gray closure) Other tube additives affect coagulation tests. Collecting the light blue top tube (for coagulation testing) in this scenario prevents contamination of the specimen with tissue thromboplastin (which will adversely affect the test).

A patient is at the lab for their weekly PT/INR. Which of the following tubes should the medical assistant collect for this test?

light blue top Sodium citrate (light blue top tube) is the anticoagulant of choice for coagulation studies such as PT/INR (Protime/International Normalization Ratio) because it does not bind to calcium or inactivate heparin, which may be required to be present in such testing. Lavender top tubes contain EDTA as the anticoagulant, which does bind calcium. Green top tubes contain heparin and could lead to inaccurate coagulation studies.

A patient with an order for a blood draw presents with burns covering both arms. Which of the following is the medical assistant's best option for collecting the largest amount of blood for this patient?

microtainer tube A microtainer tube would be the best choice in this case. If a patient has burns covering both arms, a routine venipuncture from a brachial vein is not an option. The person collecting the blood will have the best chance at getting the highest volume of blood from a smaller vein using a microtainer tube (has less vacuum pressure than a regular sized tube). There are many ways to collect blood, and using a evacuated tube is generally the best method. But in case of a burn, the best procedure would be to do a capillary finger stick and then use a microtainer tube which works on the same principle. A PKU is collected on a Guthrie blot card and is only for newborn screening.

What item is more commonly found on a phlebotomy tray?

multi-sample needle Of the choices provided, only the multi-sample needle would be commonly found on a phlebotomy tray. The typical length of such a needle varies from 1 to 1.5 inches, much longer than the 5/8 inch needle commonly used for injections. Neither sterile water nor saline are used in typical phlebotomy procedures, but do have other uses. Sterile water may be used in rehydrating a medication for injection. Normal saline (0.90% solution of Sodium Chloride or NaCl) may be used intravenously (IV).

For which of the following patients is the use of an adhesive bandage contraindicated?

newborn with hyperbilirubinemia The person collecting a blood sample from a newborn with hyperbilirubinemia would not use an adhesive bandage post-stick. Bleeding would be stopped by direct pressure and no bandage would be utilized. It is not recommended to use a bandage on children under two years of age because it could introduce a choking hazard if the child works the bandage loose. Bandaging a newborn's foot is a controversial issue because of skin sensitivity and potential bandage aspiration. Sensitivity is of particular concern in newborns with hyperbilirubinemia as they must endure multiple sample collections. Still, the incision should be monitored for bleeding and inflammation. It would be acceptable to use an adhesive bandage on the other patients in this example unless there was an indication specified, such as a latex allergy. After drawing an adult with hemophilia, the phlebotomist should monitor the venipuncture site to ensure a platelet plug has formed to stop bleeding before bandaging the patient. There are no additional requirements for using a sterile adhesive bandage on an immunocompromised child or an adolescent with sickle cell anemia.

The phlebotomist is drawing blood from a patient that is taking blood thinners. What is a necessary piece of additional equipment to have at the drawing station?

non-adhering bandage Non-adhering bandage material would be helpful for patients on anticoagulant therapy who may bleed more extensively than typical patients after venipuncture. It is necessary to contain the bleed with a bandage, but adhesive might bruise once removed from a patient who has anticoagulated blood.

Capillary blood specimen collections are contraindicated in patients with

peripheral edema. Patients with peripheral edema have a great deal of fluid in their tissue. Collection of capillary blood would provide a sample that is likely to be highly diluted with tissue fluid, affecting laboratory test results. Capillary testing would be a choice for the other patient conditions.

What site should the medical assistant use for newborn screening blood collection?

plantar surface of the heel A heel stick should be performed on the lateral or medial portions of the plantar surface of the heel-skin surface (left and right). Never stick the center area of heel, the arch, or the back of the heel. Avoid puncturing the bone by targeting the plantar surface. Draw an imaginary line starting in the middle of the big toe to the back of the heel. Then draw another imaginary line between the small toes to the back of the heel. The proper collection sites will be the fleshy portions outside those lines and below where the arch meets the heel. The anteromedial aspect, lateral surfaces and plantar curvature do not provide good flesh for a proper collection.

A phlebotomist has received a requisition to collect a blood specimen on patient in isolation. When entering the patient's room, which should the phlebotomist do first?

put on the gown Ratio nale The phlebotomist should put on the gown, followed by the mask and gloves. To reduce the risk of contaminating oneself with infectious agents, the order of removal of personal protective equipment is important. As a rule, remove items in the following order: gloves, mask, then gown.

While performing a venipuncture, immediately before removing the needle, the medical assistant should

release the tourniquet. Right before the medical assistant removes the needle, he/she should release the tourniquet. If the tourniquet is left on for too long, blood flow to the extremity could be impaired. Activating the needle safety mechanism, inverting the evacuated tubes, and applying a gauze dressing are all actions that need to be taken after the tourniquet is released and the needle is removed.

The patient reports feeling faint, and slumps forward during a venipuncture. After calling for assistance, which of the following actions should the medical assistant take next?

remove the tourniquet The procedure should be discontinued immediately, with the initial step of releasing the tourniquet. The needle would also need to be removed, but the tourniquet should be removed first because it is causing pressure to the vein. Since the needle is being removed, activating the needle safety mechanism before removing the tourniquet would not be appropriate. The medical assistant should not continue obtaining the specimen, because the patient is clearly not tolerating the procedure.

When performing venipuncture on a patient with a left mastectomy, what site should the medical assistant use?

right antecubital fossa Due to the mastectomy, avoid any left side sites. The right antecubital fossa is the best collection site. Blood samples should not be collected from the arm on any side a patient has had breast cancer surgery (a mastectomy or a lumpectomy with lymph node removal). The presence of lymph fluid dilutes the blood in this area, causing erroneous patient test results. The lymph fluid may also make the patient's arm swell, thus making tourniquet application painful. Additionally, all skin punctures should be avoided on the side of breast cancer surgery. Not only could test results be altered, but the performance of venipuncture, skin puncture, injections, etc. on breast cancer surgery patients may lead to the development of a bacterial infection. The right saphenous vein in the leg would not be a good choice (use the antecubital in the arm instead).

A centrifuge functions in which of the following ways?

rotates to separate components of a patient's blood A centrifuge rotates to separate components of a patient's blood. Depending on specimen requirements for a particular test, certain samples must be processed by centrifugation to maintain the integrity for testing. A centrifuge does not serve as a specimen warmer, nor does it magnify sample components (microscopes are used for magnification). Glucose measurements are obtained by analyzing the sample on a glucose meter or designated laboratory instrument, not the centrifuge

Which of the following is a likely complication from repeated phlebotomy procedures in the same area?

sclerosed veins Repeated punctures in a vein would cause hardening of the vessel tissue, known as sclerosis. Thrombosis refers to clot formation. Petechiae are tiny red or purple spots on the skin caused by broken capillaries. Varicose veins are caused by weakened valves and veins in the legs. One-way vein valves typically keep blood flowing from the legs up toward the heart, but when they don't work properly, blood collects in the legs and pressure builds. The veins become weak, large, and twisted.

Which of the following is the additive in the light blue top tube?

sodium citrate Lavender top tube = EDTA, Light blue top tube = sodium citrate, Green (dark) top tube = heparin, Gray top tube = potassium oxalate

A syringe is preferred over a vacuum collection device when

the patient's veins are fragile. A needle and syringe would be chosen over a vacuum collection device when a patient has fragile veins. The vacuum pressure of evacuated tubes can collapse small or fragile veins such as those on the back of the hand. When many tests requiring multiple tubes are collected, vacuum devices are preferred. A capillary puncture would be indicated for a newborn screening PKU test since it is collected on filter paper.

Blood cultures are always drawn first because?

to avoid contamination of the cultures. When sepsis is suspected, the physician orders blood cultures. Specimen collection for blood cultures is more detailed than for routine venipuncture, thus adding collection time. Blood cultures are always drawn first to avoid contamination from drawing additional tubes. It is necessary to disinfect the draw site before collecting blood cultures so they are not contaminated with normal skin flora. Contamination can result in unreliable test results, which in turn can lead to incorrect diagnosis and treatment of the patient. Blood culture bottles are sterile and the different colored tops indicate different additives.

When inserting a needle during venipuncture, the bevel should be in which of the following positions in relation to the vein?

up Positioning the needle bevel (slanted opening at the end of needle) up helps to maintain the integrity and position of the vein. If the bevel was down or to the left or right, it would not be as easy to hit the vein, and could cause damage to the tissue.

In which of the following time frames should a tourniquet be routinely released on a patient while performing a blood draw?

within one minute The standard time limit for having a tourniquet on a patient is one minute. Inaccurate laboratory test results may occur if a tourniquet is not removed within one minute. When a tourniquet is applied, the local blood flow is stopped. This leads to concentration of the blood and blood entering the surrounding tissue. This may result in falsely high values for all protein-based analytes, increased packed cell volume, and changes in other cellular elements. The most current edition of the CLSI Procedures for the Collection of Diagnostic Blood Specimens by Venipuncture, H3-A6, states that the tourniquet application for preliminary vein selection should not exceed one minute. For most patients, it is easy to release the tourniquet within the one-minute period. Most veins are easily located and the venipuncture procedure can be completed quickly.