Chapter 7: Blood Collection Equipment, Additives, and Order of Draw

21. Needle safety features work by a. covering or shielding the needle. b. retracting the needle after use. c. using a device to blunt the needle. d. All of the above.

21. Answer: d WHY: Needle safety devices include devices that shield the needle automatically as it is removed from the vein (Fig. 7-6A), blunting devices, and devices that require manual activation after use (Fig. 7-6B).

1. Which blood specimen additive can inhibit the metabolism of glucose by the cells? a. EDTA b. Heparin c. NaF d. Oxalate

1. Answer: c WHY: A substance that prevents glycolysis, the breakdown, or metabolism of glucose (blood sugar) by blood cells, is called a glycolytic inhibitor or an antiglycolytic agent. The most common antiglycolytic agent is sodium fluoride (NaF). It preserves glucose for up to three days and also inhibits the growth of bacteria.

10. Measurement of copper, a trace element, normally requires blood collection in a tube with a a. green top. b. lavender top. c. light blue top. d. royal blue top.

10. Answer: d WHY: Royal blue-top tubes are made of materials that are as free of trace-element contamination as possible and are used for trace-element tests, such as copper.

26. Plastic red-top tubes used to collect blood specimens contain a. anticoagulants. b. clot activators. c. no additives. d. preservatives.

26. Answer: b WHY: Plastic red-top tubes are for collecting serum specimens and contain a clot activator. With the advent of plastic tubes, few tubes are additive-free anymore. Even serum tubes have an additive if they are plastic because plastic is so slick that platelet aggregation and adhesion is inhibited unless the tube contains a clot activator.

44. Multisample needles are typically available in which gauges? a. 16 to 18 b. 18 to 20 c. 20 to 22 d. 22 to 24

44. Answer: c WHY: ETS multisample needles (see Figs. 7-6 Refer to #21 and 7-10) are generally available in 20-, 21-, and 22-gauge. A 21-gauge needle is considered the standard needle for routine venipuncture. Syringe needles and butterfly needles are available in smaller-size gauges for difficult draw situations.

64. During venipuncture, the tourniquet should not be left on longer than a. 30 seconds. b. 1 minute. c. 2 minutes. d. 5 minutes.

64. Answer: b WHY: Proper tourniquet application allows arterial blood flow into the area below the tourniquet but obstructs venous flow away from the area. This causes the veins to enlarge and makes them easier to find and pierce with a needle. However, the obstruction of blood flow can change blood components if the tourniquet is left in place for more than 1 minute.

98. While collecting a STAT blood culture and electrolytes on a child in the emergency room, the physician asked the phlebotomist to get an extra tube of blood to check for metal poisoning. Which of the following tubes would the phlebotomist add to the ones already being collected? a. Gold b. Gray c. Pink d. Royal blue

98. Answer: d WHY: The royal blue-top tubes are used for toxicology studies, which would include metal poisoning. Royal blue stoppers indicate trace element-free tubes. These tubes are used for substances present in such small quantities that trace-element contamination commonly found in other tubes may leach into the specimen and falsely elevate test results. A trace-element tube should be collected separately or a syringe used for the draw and the transfer device changed before filling the royal blue top. This minimizes the chance of contamination picked up by the transfer needle from the stoppers of other tubes filled before it.

99. Which of the following tubes/additives would be used to collect a DNA test? a. Gold/clot activator b. Light green/heparin c. Yellow/ACD d. Yellow/SPS

99. Answer: c WHY: The yellow-top tube containing ACD solution is available in two formulations (solution A and solution B) for immunohematology tests such as DNA testing used in paternity evaluation. The acid citrate prevents coagulation by binding calcium, with little effect on cells and platelets. Dextrose acts as a red blood cell nutrient and preservative by maintaining red cell viability.

100. Electrolytes should never be collected in a a. gold top. b. gray top. c. light green top. d. red/gold top.

100. Answer: b WHY: The most common electrolytes tested are sodium and potassium. A gray-top tube typically contains sodium fluoride and potassium oxalate that would greatly increase sodium and potassium results. A tube with a light green top contains lithium heparin, which is the preferred additive for electrolyte testing. Tubes with gold or red and black tops are serum separator tubes. Although recent studies suggest plasma is the preferred specimen for electrolytes testing, many labs still use serum specimens.

11. The blood to additive ratio is most critical for a specimen collected in which tube? a. Lavender top b. Light blue top c. Light green top d. Royal blue top

11. Answer: b WHY: Coagulation tests are collected in light blue-top tubes containing liquid sodium citrate. For accurate results, coagulation tests require a 9:1 ratio of blood to additive. If tubes are not filled to within 90% of the stated volume, dilution of the blood occurs that can falsely elevate test results. Some tubes have arrows to show minimum to maximum fill levels (Fig. 7-2).

12. If phlebotomists develop dermatitis on their hands, they should a. change their gloves more frequently. b. see if wearing glove liners will help. c. use sanitizer instead of soap and water. d. wash their hands thoroughly and often.

12. Answer: b WHY: Dermatitis is a condition that can be caused by wearing gloves, required frequent handwashing, and drying effects of alcohol-based hand sanitizers. Since frequent hand decontamination is necessary when performing phlebotomy, wearing glove liners (Fig. 7-3) might help prevent skin irritation.

13. Decontamination of hands after glove removal is essential because a. decontamination is needed to quickly restore normal flora. b. gloves cause pathogens to multiply on surface of the skin. c. hand contamination might not be visible to the naked eye. d. All of the above.

13. Answer: c WHY: Any type of glove may contain defects, and contamination is not always visible. Consequently, decontamination of hands after glove removal is essential and made very convenient, for instance, by wall-mounted hand sanitizer dispensers (Fig. 7-4).

14. Which of the following is a disinfectant? a. Benzalkonium chloride b. Chlorhexidine gluconate c. Household bleach d. Hydrogen peroxide

14. Answer: c WHY: Household bleach, or 5.25% sodium hypochlorite, is an effective disinfectant. Disinfectants are not safe to use on skin. The other choices are antiseptics, which are safe to use on skin (Box 7-1).

15. Which disinfectant is preferred by the HICPAC for use on surfaces and instruments? a. CDC-approved solution of 2% phenol b. Commercial brand of Lysol disinfectant c. Manufactured povidone-iodine dilution d. EPA-registered sodium hypochlorite product

15. Answer: d WHY: According to CDC and HICPAC Guidelines for Environmental Infection Control in Healthcare Facilities, use of EPA-registered sodium hypochlorite products for disinfecting surfaces and instruments is preferred.

16. A disinfectant applied to a blood spill must have at least __________ minutes of contact time for cleanup to be effective. a. 2 b. 5 c. 10 d. 30

16. Answer: c WHY: A spill involving large amounts of blood or other body fluids requires at least 10 minutes of contact time with a disinfectant for the cleanup to be considered effective.

17. If hands are heavily contaminated with organic material and a sink for hand washing is not available, the phlebotomist should clean them with a. alcohol-based hand cleaner and sterile gauze pads. b. detergent-containing wipes followed by a sanitizer. c. hydrogen peroxide followed by a hand sanitizer. d. three separate 70% isopropyl swabs used in a row

17. Answer: b WHY: When hands are heavily contaminated with organic material and a sink for handwashing is not available, it is recommended that hands be cleaned with detergent-containing wipes followed with use of an alcohol-based hand sanitizer.

18. The purpose of a transillumination device is to a. input patient ID information. b. locate veins for venipuncture. c. transfer blood from a syringe. d. All of the above.

18. Answer: b WHY: Transillumination is the inspection of an organ by passing light through its walls. Transillumination devices can be used to locate veins. They work by shining a high-intensity light through the patient's skin. Veins, which absorb the light rather than reflecting it, stand out as dark lines (Fig. 7-5).

19. A properly applied tourniquet should do all of the following EXCEPT a. distend or inflate the veins of choice. b. make veins larger and easier to find. c. restrict venous and arterial blood flow. d. stretch vein walls so they are thinner.

19. Answer: c WHY: A properly applied tourniquet is tight enough to restrict venous flow out of the area, but not so tight as to restrict arterial flow into the area. Restriction of venous flow distends or inflates the veins, making them larger and easier to find, and stretches the vein walls, making them thinner and easier to pierce with a needle.

2. All of the following items are part of the equipment needed to perform a routine venipuncture EXCEPT which? a. Disinfectant b. Evacuated tubes c. Safety needle d. Tourniquet

2. Answer: a WHY: Antiseptics, not disinfectants, are routinely used when performing venipuncture. Disinfectants are chemical substances or solutions that are used to remove or kill microorganisms on surfaces and instruments. They are typically corrosive and not safe for use on human skin.

20. Which needle gauge is used for autologous blood collection? a. 15 to 17 b. 18 to 21 c. 21 to 23 d. 23 to 25

20. Answer: a WHY: Needles that are 15- to 17-gauge are used for autologous blood donation, collection of donor units of blood, and for therapeutic phlebotomy (Table 7-1).

22. OSHA regulations require that after use, needles must be a. automatically ejected from the holder into a sharps container. b. disposed of with needle and tube holder still attached as a unit. c. removed from the tube holders immediately before disposal. d. removed so that the tube holders can be sanitized and reused.

22. Answer: b WHY: OSHA regulations require that the tube holder with needle still attached be disposed of as a unit in the sharps container immediately after use. OSHA guidelines state that the needle should not be removed from the tube holder and that the tube holder should not be reused.

23. The headspace in an evacuated tube is a. a consistent amount of air space left when a tube is filled properly. b. due to premature depletion of tube vacuum when a vein is missed. c. room left in a tube if the tube is not completely filled with blood. d. space inside a colored tube stopper that should not touch the blood.

23. Answer: a WHY: Evacuated tubes fill with blood automatically because they have a vacuum. The vacuum is premeasured by the manufacturer so that the tube will draw the precise volume of blood indicated. Tubes do not fill with blood all the way to the stopper. When filled properly, there is always a consistent amount of headspace between the level of blood in the tube and the tube stopper.

24. Tubes designed by the manufacturer to be "short draw" are a. bad for coagulation testing. b. made to fill only partially. c. smaller than regular tubes. d. tubes without anticoagulants.

24. Answer: b WHY: Some manufacturers offer special "short-draw" (Fig. 7-7) tubes designed to partially fill without compromising test results. These tubes are used in situations in which it is difficult or inadvisable to draw larger quantities of blood. They are typically the same size as regular-fill tubes but contain adjusted amounts of additive. The short-draw tubes can be used for any of the tests for which regular tubes are used.

25. Types of ETS tube additives include a. anticoagulants. b. clot activators. c. separator gels. d. All of the above.

25. Answer: d WHY: Most ETS tubes contain some type of additive. An additive is any substance placed within a tube other than the tube stopper or the coating of the tube. Additives include anticoagulants, clot activators, preservatives, and separator gels.

27. Improper handling or storage of evacuated tubes can affect a. additive integrity. b. shape of the tube. c. vacuum of a tube. d. All of the above.

27. Answer: d WHY: Improper handling or storage may affect additive integrity and tube vacuum, which can lead to compromised test results or improper filling, respectively. If plastic tubes are not stored properly, heat can cause them to soften and become distorted.

28. Which would be the best tube for collecting a STAT test that must be performed on serum? a. PPT b. PST c. RST d. SST

28. Answer: c WHY: A rapid serum tube (RST) contains thrombin, which normally clots the blood in 5 minutes. A plasma preparation tube (PPT) and a plasma separation tube (PST) provide plasma for testing, not serum. A serum separator tube provides serum but can take up to 30 minutes to clot.

29. Which additive is used to collect donor units of blood? a. ACD b. CPD c. SPS d. All of the above

29. Answer: b WHY: CPD stands for citrate phosphate dextrose, which is used to collect units of blood for transfusion. Acid citrate dextrose (ACD) is used in immunohematology for tests such as HLA phenotyping. Sodium polyanethol sulfate (SPS) is found in tubes used to collect blood cultures.

3. Which of the following evacuated tubes can be used to collect a serum specimen? a. EDTA b. PPT c. PST d. SST

3. Answer: d WHY: SST stands for serum separator tube. The tube does not contain an anticoagulant, so blood collected in it will yield serum. The EDTA tube and plasma preparation tube (PPT) both contain the anticoagulant EDTA. The plasma separator tube (PST) contains the anticoagulant heparin. Anticoagulants prevent the blood from clotting and yield plasma when centrifuged.

30. A specimen collected in which type of additive will separate if allowed to stand? a. Citrate b. Heparin c. Oxalate d. All of the above

30. Answer: d WHY: Citrates, heparin, and oxalates are all anticoagulants, so the cells will be free-flowing and not clotted. That means they will separate from the plasma if allowed to stand for an extended amount of time or if the specimen is centrifuged.

31. What is the advantage of collecting STAT chemistries in a green-top tube? a. Plasma specimens can be centrifuged right away. b. The turnaround time for results is much shorter. c. Whole blood tests can be performed right away. d. All of the above.

31. Answer: d WHY: Green-top tubes contain heparin. The big advantage of performing STAT chemistry tests on heparinized specimens is a faster turnaround time (TAT) for test results than when serum is used. Heparinized specimens for plasma tests can be centrifuged right away, whereas serum specimens must be clotted which can take up to 30 minutes or more. Whole blood chemistry tests can be performed right away.

32. Which antiseptic was traditionally used to obtain the high degree of skin antisepsis required when collecting blood cultures? a. 70% ethyl alcohol b. 70% isopropanol c. Hydrogen peroxide d. Povidone-iodine

32. Answer: d WHY: Collection of some specimens, such as blood cultures, requires a higher degree of skin antisepsis than obtained by using isopropyl alcohol. Povidone-iodine, in the form of swabsticks or sponge pads, has been the traditional skin antiseptic used to collect these specimens. The use of an alcohol-based preparation for these procedures is increasing, however, because many patients are allergic to povidone-iodine. Antiseptics used in blood collection are listed in Box 7-1.

33. Which of the following is the preferred solution to use to clean up blood spills? a. 5.25% sodium hypochlorite b. An EPA-approved bleach product c. Fresh solution of soap and water d. Undiluted 70% isopropyl alcohol

33. Answer: b WHY: According to CDC and HICPAC Guidelines for Environmental Infection Control in Healthcare Facilities, use of EPA-registered or approved sodium hypochlorite products is preferred, but solutions made from 5.25% sodium hypochlorite (household bleach) may be used. A 1:100 dilution is recommended for decontaminating nonporous surfaces after cleaning up blood or other body fluid spills in patient care settings.

34. Antiseptics are a. corrosive chemical compounds. b. safe for use on human skin. c. used on surfaces and instruments. d. used to kill pathogenic microbes.

34. Answer: b WHY: Disinfectants are corrosive chemical compounds that are bactericidal (kill bacteria). Some also kill viruses such as human immunodeficiency virus and hepatitis. Disinfectants are used on surfaces and instruments to kill potential pathogens, but are not safe for use on human skin. Antiseptics are safe for use on human skin.

35. Which of the following is used to clean the site before routine venipuncture? a. 5.25% sodium hypochlorite b. 70% isopropyl alcohol c. 70% methanol d. Povidone-iodine

35. Answer: b WHY: The most common antiseptic used for routine blood collection is 70% isopropyl alcohol (isopropanol) in the form of individually wrapped prep pads (Fig. 7-8). Bleach (5.25% sodium hypochlorite) is a disinfectant and is not safe to use on human skin. Methanol can be toxic when absorbed through the skin and is not used as a skin antiseptic. Povidone-iodine is sometimes used for collection of sterile specimens such as blood cultures.

36. Why are gauze pads a better choice than cotton balls for covering the site and holding pressure following venipuncture? a. Cotton balls are not very absorbent. b. Cotton ball fibers can stick to the site. c. Gauze pads are a more sterile choice. d. Gauze pads deliver more pressure.

36. Answer: b WHY: Gauze or gauze-like pads are preferred for holding pressure over a venipuncture site because the fibers from cotton, Dacron, or rayon balls tend to stick to the site and reinitiate bleeding when removed, by dislodging the platelet plug.

37. CLSI standards advise against using which product on infants and children younger than 2 years of age? a. Adhesive bandages b. Evacuated tubes c. Isopropyl alcohol d. Vinyl tourniquets

37. Answer: a WHY: Adhesive bandages should not be used on infants and children younger than 2 years of age because of the danger of aspiration and suffocation if they are accidentally removed from the site. They can also tear the delicate skin of infants, especially newborns.

38. Which of the following should be deleted from a list of required characteristics of a sharps container? a. Leak-proof b. Lid that locks c. Puncture-resistant d. Red in color

38. Answer: d WHY: The Occupational Safety and Health Administration (OSHA) requires that sharps containers (Fig. 7-9) be rigid, leak-proof, puncture-resistant, disposable, and have locking lids that can be easily sealed when the container is filled to its stated capacity. OSHA also requires that they be marked with a biohazard symbol, but they do not require that all of the containers be red.

39. It is best if tourniquets are a. cleaned daily with bleach. b. thrown away when soiled. c. used once and then discarded. d. wiped with alcohol after use.

39. Answer: c WHY: Although currently there is no regulatory requirement to dispose of tourniquets after one use, several studies have shown that reusable tourniquets have the potential to transmit bacteria, including methicillin-resistant Staphylococcus aureus (MRSA). Consequently, the best infection control measure is to use a new tourniquet for each patient. Bleach disintegrates latex and makes it gummy. Alcohol is an antiseptic and would not necessarily destroy pathogens. Disposable tourniquets should be discarded when soiled, but microorganism contamination is invisible, which is why it is best not to reuse them in the first place.

4. Which of the following are all anticoagulants that prevent coagulation by binding or precipitating calcium? a. EDTA, lithium heparin, citrate b. NaF, sodium heparin, EDTA c. Oxalate, SPS, sodium heparin d. Sodium citrate, EDTA, oxalate

4. Answer: d WHY: Sodium citrate, oxalate, and EDTA are all anticoagulants that prevent blood from clotting by chelating (binding) or precipitating calcium so it is not available to the coagulation process. Sodium polyanethol sulfonate (SPS) also binds calcium, though lithium and sodium heparin prevent clotting by inhibiting the formation of thrombin needed to convert fibrinogen to fibrin in the coagulation process. Sodium fluoride (NaF) is an antiglycolytic agent, not an anticoagulant.

40. Wearing gloves during phlebotomy procedures is mandated by which agency? a. CDC b. FDA c. HICPAC d. OSHA

40. Answer: d WHY: OSHA's Bloodborne Pathogen Standard is a federal law that mandates wearing gloves during most phlebotomy procedures. The CDC and HICPAC provide guidelines for wearing gloves, but the guidelines are not federal laws. The FDA regulates glove quality.

41. What criterion is used to decide which needle gauge to use for venipuncture? a. Depth of the selected vein b. Size and condition of the vein c. Type of test being collected d. Your personal preference

41. Answer: b WHY: The needle gauge for venipuncture is selected according to the size and condition of the patient's vein, the type of procedure, and the equipment being used. Personal preference and the depth of the vein influence the length of needle used, rather than the gauge. The type of test being collected does not normally influence selection of the needle gauge or length.

42. To what does the "gauge" of a needle relate? a. Diameter b. Length c. Strength d. Volume

42. Answer: a WHY: The gauge of a needle is a number that is inversely related to the diameter of the lumen or internal space of the needle. It is an indication of the size of the needle; the larger the number, the smaller its diameter and vice versa. Most needles are color-coded according to gauge; however, color coding can vary by manufacturer. Multisample needles typically have color-coded caps. Several manufacturers use yellow for 20-gauge, green for 21-gauge, and black for 22-gauge needles (see Figs. 7-6 Refer to #21 and 7-10).

43. Which needle gauge has the largest bore or lumen? a. 18 b. 20 c. 21 d. 22

43. Answer: a WHY: "Bore" is a term used to describe the diameter of a needle and the size of the hole it makes. There is an inverse relationship between the gauge number and the bore or diameter of the lumen of a needle. Therefore, the needle gauge with the largest bore or lumen is the one with the smallest number.

45. The slanted tip of a needle is called the a. bevel. b. hub. c. lumen. d. shaft.

45. Answer: a WHY: The end of the needle that is inserted into the vein is called the bevel because it is cut on a slant, or "beveled," to allow the needle to penetrate the vein easily and prevent coring (removal of a portion of the skin or vein). The hub of a needle is the end that attaches to a syringe or tube holder. The lumen of a needle is the internal space of the needle. The shaft is the long cylindrical part of the needle. ETS needle parts are shown in Figure 7-11.

46. The purpose of the rubber sleeve that covers the tube end of a multiple-sample needle is to a. enable smooth tube placement and removal. b. maintain the sterile condition of the sample. c. prevent leakage of blood during tube changes. d. protect the needle and help keep it sharp.

46. Answer: c WHY: The rubber sleeve (see Fig. 7-11) of a multiple-sample needle retracts as the needle is inserted into the tube, allowing the tube to fill with blood, and recovers the needle as the tube is removed, preventing leakage of blood into the tube holder. It is not possible to maintain a sterile sample unless the sample is collected in a sterile manner. The flanges on the holder were designed to enable smooth tube placement and removal.

47. A phlebotomy needle that does not have a safety feature a. cannot be used for any venipuncture procedure. b. must be used with a holder that has a safety feature. c. requires immediate recapping after venipuncture. d. should be removed from the holder before disposal.

47. Answer: b WHY: A needle without a safety feature (see Fig. 7-10 Refer to #44 ) can be used for blood collection. However, according to OSHA regulations, it must be used with a tube holder that has a safety feature (Fig. 7-12). In addition, a needle must never be recapped or removed from its holder after use unless it has been demonstrated that it is specifically required by a medical procedure or there is no feasible alternative. In such instances, a mechanical device or some method other than a two-handed procedure must be used.

48. All of the following play a role in deciding what size tubes to use for ETS blood collection EXCEPT a. age and weight of the patient. b. patient's allergy to antiseptics. c. sample size needed for testing. d. size and condition of the veins.

48. Answer: b WHY: The size and condition of the patient's vein and sample volume required for testing play a major role when selecting the size of tubes to use for venipuncture. Age and weight play a role when drawing infants and young children so as not to deplete their blood volumes. Age is also a consideration when drawing elderly patients with fragile veins. Allergies play a role in selecting the antiseptic to use, not tube size.

49. Mixing additive tubes involves a. gently shaking them up and down. b. slowly rocking them back and forth. c. turning the wrist 90 degrees and back. d. turning the wrist 180 degrees and back.

49. Answer: d WHY: Additive tubes require mixing by inversion. The number of inversions depends upon the type of additive and manufacturer instructions. One inversion is defined by tube manufacturer Becton Dickinson (BD) as a turn of the wrist of 180 degrees and back again.

5. During a successful venipuncture, evacuated tubes fill automatically when the tube stopper is pierced because of a. equal pressure in the vein and tube. b. premeasured vacuum in each tube. c. pressure from the arterial system. d. tourniquet pressure on the vein.

5. Answer: b WHY: Evacuated tubes fill with blood automatically because there is a vacuum (negative pressure) in them. The vacuum is premeasured by the manufacturer so that the tube will draw the precise volume of blood indicated.

50. Which of the following stopper colors identifies a tube used for coagulation testing? a. Green b. Lavender c. Light blue d. Red

50. Answer: c WHY: A light blue-top tube typically contains the anticoagulant sodium citrate as the additive. Sodium citrate prevents coagulation by binding calcium. It is used for coagulation specimens because it does the best job of preserving the coagulation factors and adding calcium back to the specimen during testing easily reverses its binding effects. The most common use of green tops is to collect plasma for chemistry tests. Lavender tops are most commonly used to collect whole blood for hematology tests. Red tops are most often used for chemistry, serology, and blood bank tests.

51. Which of the following tubes will yield a serum sample? a. Green top b. Lavender top c. Light blue top d. Red top

51. Answer: d WHY: There are two types of red-top tubes, glass and plastic. Blood collected in either of these tubes will clot, and when centrifuged, a clear fluid called serum separates from the clotted cells. Green, lavender, and light blue-top tubes contain anticoagulants. Specimens that are collected in anticoagulant tubes are prevented from clotting and yield whole-blood specimens. When blood in anticoagulant tubes is centrifuged, clear fluid separates from the cells and is called plasma. Green-top tubes are typically centrifuged to yield plasma for certain chemistry tests. The most common use of light blue tops is to provide plasma for coagulation tests.

52. The CDC-recommended cleaning agent in hand sanitizers used in healthcare is a. alcohol-based. b. phenol-based. c. sodium hypochlorite. d. zephiran chloride.

52. Answer: a WHY: The CDC Guideline for Hand Hygiene in Healthcare Settings recommends the use of alcohol-based hand sanitizers as a substitute for handwashing, provided the hands are not visibly soiled.

53. Which of the following tube stopper colors indicates something other than the presence (or absence) and type of additive in the tube? a. Green b. Lavender c. Light blue d. Royal blue

53. Answer: d WHY: Most tube stopper colors indicate the presence (or absence) and type of additive in a tube. A green stopper indicates heparin, a lavender stopper indicates EDTA, and light blue normally indicates sodium citrate. A royal blue stopper, however, indicates that the tube and stopper are virtually trace element-free. A royal blue top can contain no additive, potassium EDTA, or sodium heparin. Additive color coding of a royal blue-top tube is typically indicated on the label.

54. Heparin prevents blood from clotting by a. activating calcium. b. binding calcium. c. chelating thrombin. d. inhibiting thrombin.

54. Answer: d WHY: Heparin prevents coagulation by inhibiting thrombin during the coagulation process. Thrombin is necessary for the formation of fibrin from fibrinogen. Without thrombin, a fibrin clot cannot form.

55. Which department would most likely perform the test on a specimen collected in an SPS tube? a. Chemistry b. Coagulation c. Hematology d. Microbiology

55. Answer: d WHY: Sodium polyanethol sulfonate (SPS) tubes are used to collect blood cultures, which are performed in the microbiology department. SPS is an anticoagulant with special properties that inhibits proteins that destroy bacteria, prevents phagocytosis of bacteria by white blood cells, and reduces the activity of some antibiotics.

56. A royal blue-top tube with green color coding on the label contains a. EDTA. b. heparin. c. no additive. d. sodium citrate.

56. Answer: b WHY: A royal blue stopper signifies that the tube and stopper contain the lowest levels of trace elements available (i.e., they are virtually trace element-free). Royal blue-top tubes are available with EDTA, heparin, no additive (glass tube), or clot activator (plastic tube). Color coding on the label indicates what additive, if any, is in the tube. Green color coding on the label of a royal blue top indicates that it contains heparin.

57. Which one of the following substances is an anticoagulant? a. Oxalate b. Phosphate c. Silica d. Thrombin

57. Answer: a WHY: Oxalate is an anticoagulant that prevents coagulation by precipitating calcium and the form most widely used is potassium oxalate. Thromboplastin is found in tissue fluid and activates the extrinsic clotting pathway. Silica is used as a clot activator in ETS clotting tubes. Phosphate is an additive found in the special anticoagulants, ACD and CPD.

58. It is important to fill oxalate tubes to the stated fill capacity because excess oxalate a. causes hemolysis of blood specimens. b. changes white blood cell staining characteristics. c. erroneously increases potassium levels. d. leads to the formation of microclots.

58. Answer: a WHY: Excess oxalate causes hemolysis, the destruction of red blood cells and the liberation of hemoglobin into the plasma. Hemolysis will increase potassium levels, but the gray-top tube containing potassium oxalate as the anticoagulant cannot be used to collect potassium specimens. Microclot formation can result from too little anticoagulant, rather than too much. Hematology tests, such as evaluating stained WBCs, are collected in EDTA tubes, not oxalate.

59. Which of the following substances is contained in a serum separator tube? a. K3EDTA b. Lithium heparin c. Sodium citrate d. Thixotropic gel

59. Answer: d WHY: Thixotropic gel is an inert (nonreacting) synthetic substance that forms a physical barrier between the cellular portion of a specimen and the serum or plasma portion after the specimen has been centrifuged. The gel is normally found in or near the bottom of the tube. When used in a serum tube, it is called serum separator, and the tube is referred to as a serum separator tube (SST) or a gel-barrier tube. When used in a tube that contains heparin, it is called plasma separator and the tube is referred to as a plasma separator tube (PST). If it is used in a tube that contains EDTA, the tube is called a plasma preparation tube (PPT). Gels do not contain sodium citrate. Gel can be seen in the second and fourth tubes from the left in Figure 7-13.

6. Lavender stopper tubes are most commonly used to collect a. chemistry tests. b. coagulation tests. c. hematology tests. d. immunology tests.

6. Answer: c WHY: EDTA prevents coagulation and is primarily used to provide whole blood specimens for hematology tests because it preserves cell morphology and inhibits platelet aggregation or clumping.

60. What is the purpose of an antiglycolytic agent? a. Enhancing the clotting process b. Inhibiting electrolyte breakdown c. Preserving glucose d. Preventing clotting

60. Answer: c WHY: An antiglycolytic agent is a substance that inhibits or prevents glycolysis (metabolism of glucose) by the cells of the blood. The most common glycolytic inhibitors are sodium fluoride and lithium iodoacetate.

61. Glass particles present in serum separator tubes a. enhance clotting. b. deter coagulation. c. inhibit glycolysis. d. prevent hemolysis.

61. Answer: a WHY: Glass (silica) particles are called clot activators and are present in serum separator tubes to make the blood more clot completely. Glass particles enhance clotting by providing increased surface for platelet activation, aggregation, and adhesion. Other substances that function as clot activators in other types of tubes include inert clays such as kaolin, celite, and the clotting components thromboplastin and thrombin.

62. The best tube for collecting an ETOH (ethanol) specimen has which color stopper? a. Gray top b. Green top c. Lavender top d. Light blue top

62. Answer: a WHY: A gray-top tube typically contains sodium fluoride, which prevents glycolysis. It is used for alcohol determinations and glucose tests. Alcohol values are stable because glycolysis (the metabolism of glucose or sugar in the form of alcohol) is prevented. Sodium fluoride also inhibits growth of bacteria and protects the specimen from an increase in alcohol resulting from fermentation by bacteria.

63. Identify the tubes needed to collect a CBC, PTT, and STAT potassium by color and in the proper order of collection for a multiple tube draw. a. Gold top, yellow top, light blue top b. Lavender top, SST, royal blue top c. Light blue top, green top, lavender top d. Red top, gray top, light blue top

63. Answer: c WHY: A CBC is a hematology test collected in a lavender-top tube. A PTT is a coagulation test collected in a light blue-top tube. A STAT potassium is a chemistry test collected in a green-top tube. The proper order of draw for these tubes is light blue first, green next, and lavender last (Table 7-2).

65. Which of the following tubes is filled first when multiple tubes are filled from a syringe? a. Blood culture tube b. Complete blood count tube c. Nonadditive tube d. STAT potassium tube

65. Answer: a WHY: Tubes or containers for specimens such as blood cultures that must be collected in a sterile manner are always collected first in the order of draw for both the syringe and ETS system of venipuncture (see Table 7-2) Refer to #63.

66. Which test is collected in a light blue-top tube? a. Glucose b. Platelet count c. Prothrombin time d. Red blood cell count

66. Answer: c WHY: A prothrombin time (PT) is a coagulation test collected in a light blue-top tube containing sodium citrate. The best tube for collecting a glucose specimen is a gray top containing an antiglycolytic agent such as sodium fluoride. A platelet count is sometimes ordered to assess coagulation, but it is a hematology test collected in a lavender-top tube. A red blood cell count is a hematology test collected in a lavender-top tube.

67. Which of the following STAT tests is typically collected in a lithium heparin tube? a. Blood type and screen b. Complete blood count c. Electrolyte panel d. Prothrombin time

67. Answer: c WHY: Most chemistry tests have been traditionally performed on serum, but to save the time it takes for a serum specimen to clot before it can be tested, STAT electrolytes and other STAT chemistry tests are often performed on plasma specimens collected in lithium heparin tubes. (Sodium heparin tubes must not be used for STAT electrolytes because sodium is one of the electrolytes measured.) In fact, heparinized plasma may be the best specimen for all potassium tests because cells release potassium when they clot, which can artificially elevate results. Regardless of whether serum or plasma is used, the type of specimen should be consistent for all potassium tests on the same patient.

68. Which tube stopper color indicates that the tube contains EDTA? a. Green b. Lavender c. Light blue d. Royal blue

68. Answer: b WHY: A lavender (or purple) top indicates that the tube contains EDTA. Most hematology tests are collected in lavender-top tubes. A green stopper indicates a heparin-containing tube, and a light blue stopper indicates the presence of sodium citrate unless it has a special yellow label. A royal blue stopper indicates that the tube and stopper are as free of trace elements as possible. A royal blue stopper sometimes contains EDTA, but only if it has lavender color coding on the label or EDTA is written on the label.

69. Which anticoagulant is contained in a PST? a. ACD b. Citrate c. Heparin d. Oxalate

69. Answer: c WHY: A plasma separator tube (PST) contains heparin. Some gel-barrier tubes, such as the plasma preparation tube (PPT), contain EDTA. Serum separator tubes (SSTs) are gel-barrier tubes, but they do not contain anticoagulant. Anticoagulants are used to obtain either whole blood or plasma specimens. In the separator tubes, the plasma can be removed from the cells so that the integrity of the specimen is maintained.

7. Which of the following is one reason the evacuated tube system is the preferred blood collection system? a. Exposure of the blood to contaminants is avoided. b. Needles used with the ETS have a smaller lumen. c. The collector's exposure to blood is eliminated. d. Using a syringe can collapse a vein more easily.

7. Answer: a WHY: The most common, efficient, and CLSI-preferred system for collecting blood samples is the ETS. It is a closed system in which the patient's blood flows directly into a collection tube, without being exposed to air or outside contaminants. Blood collected in a syringe is exposed to air and the possibility of outside contamination. In addition, the needle must be removed from a syringe to attach a transfer device used to fill the tubes. This can expose the user to the patient's blood. The ETS minimizes the collector's exposure to blood but does not eliminate it as there is often a small amount of blood on the stopper where the needle entered the tube. The ETS system can collapse a fragile vein more easily than a syringe. The vacuum pull of a syringe can be adjusted to minimize the chance of vein collapse. Syringe needles are available in the same gauges as ETS needles, so an equivalent gauge ETS needle would have the same size lumen as a syringe needle.

70. The purpose of sodium citrate in specimen collection is to a. accelerate coagulation. b. inhibit glucose breakdown. c. preserve glucose values. d. protect coagulation factors.

70. Answer: d WHY: Sodium citrate is the anticoagulant contained in light blue-top tubes used to collect plasma for coagulation tests. It is used for coagulation tests because it does the best job of protecting the coagulation factors. The ratio of blood to anticoagulant is critical in coagulation testing, so it is important for sodium citrate tubes to be filled to their stated capacity.

71. The part of a syringe that shows measurements in cc or mL is called the a. adapter. b. barrel. c. hub. d. plunger.

71. Answer: b WHY: The barrel of a syringe holds the fluid being aspirated or administered and is measured in cubic centimeters (cc) or milliliters (mL). The plunger is a rod-like device that fits tightly into the barrel. Pulling on the plunger creates the vacuum that allows the barrel to fill with the fluid being aspirated. The hub is where the needle attaches to the syringe. Syringe components are shown in Figure 7-14.

72. Which part of the evacuated tube holder is meant to aid in smooth tube removal? a. Barrel b. Flange c. Hub d. Sleeve

72. Answer: b WHY: The flanges or extensions on the sides of the tube end of the holder are there to aid in tube placement and removal. Figure 7-15 shows proper placement of fingers and thumb when advancing a tube in an ETS holder.

73. The best choice of equipment for drawing difficult veins is the a. butterfly and ETS holder. b. lancet and microtainer. c. needle and ETS holder. d. needle and 10-cc syringe.

73. Answer: a WHY: A butterfly needle (Fig. 7-16) is an indispensable tool for collecting blood from small or difficult veins because it allows much more flexibility and precision than either a regular needle and evacuated tube holder or needle and syringe. A lancet and microtainer can be used to collect some specimens by skin puncture, but there are several tests that cannot be collected by this method.

74. Mixing equipment from different manufacturers can result in a. carryover of an additive. b. improper fit of the needle. c. wrong choices of additives. d. All of the above.

74. Answer: b WHY: Although evacuated tube collection system components from different manufacturers are similar, they are not necessarily interchangeable. Mixing components from different manufacturers can lead to problems such as improper needle fit and needles coming unscrewed, or tubes popping off the needle during venipuncture procedures. Color coding of tube tops is generally universal, with only a few minor variations in each company's product, so selecting the proper additive tube is not normally an issue. Carryover of additive is typically related to errors in specimen collection technique.

75. You are most likely to increase the chance of hemolyzing a specimen if you use a a. 21-gauge needle and ETS tube to collect a specimen from a median vein. b. 22-gauge needle and syringe to collect a specimen from a difficult vein. c. 23-gauge butterfly needle to collect a specimen from a hand vein. d. 25-gauge butterfly needle to collect a specimen from a small child.

75. Answer: d WHY: The 25-gauge butterfly needles are sometimes successfully used to collect blood specimens from infants and others with difficult veins. However, any time a needle smaller than 23-gauge is used to collect blood, the chance of trauma to the red blood cells and resulting hemolysis is increased.

76. The purpose of a tourniquet in the venipuncture procedure is to a. block the flow of arterial blood into the area. b. enlarge veins so they are easier to find and enter. c. obstruct blood flow to concentrate the analyte. d. redirect more blood flow to the venipuncture site.

76. Answer: b WHY: The purpose of a tourniquet in the venipuncture procedure is to block the venous flow, not the arterial flow, so that blood flows freely into the area but not out. This causes the veins to enlarge, making them easier to find and penetrate with a needle. The tourniquet does not redirect blood flow but does change the volume of the flow. The tourniquet must not be left on for longer than 1 minute because obstruction of blood flow changes the concentration of some analytes, leading to erroneous test results.

77. If a blood pressure cuff is used for venipuncture in place of a tourniquet, the pressure used must be a. below the patient's diastolic pressure. b. between the diastolic and the systolic pressure. c. equal to the patient's systolic pressure. d. equal to the patient's venous pressure.

77. Answer: a WHY: A blood pressure cuff may be used in place of a tourniquet by those familiar with its operation. The patient's blood pressure is taken, and the pressure is then maintained below the patient's diastolic pressure. In the absence of a blood pressure reading, the cuff pressure should not exceed 40 mm Hg.

78. In general, an anticoagulant is unable to a. bind calcium or inhibit thrombin. b. inhibit the metabolism of glucose. c. keep the blood in its natural state. d. prevent the specimen from clotting.

78. Answer: b WHY: An anticoagulant prevents coagulation or clotting of the blood either by binding calcium and making it unavailable to the coagulation process, or by inhibiting thrombin formation, which is needed in the coagulation process. A specimen that is not allowed to clot because of the addition of an anticoagulant remains as it was in the body and is called a whole blood sample. Anticoagulants do not inhibit glucose metabolism.

79. A needle safety device must a. allow the phlebotomist to safely activate it using both hands. b. create a barrier between a user's hand and the needle after use. c. provide temporary containment of the used venipuncture needle. d. All of the above.

79. Answer: b WHY: A needle safety device (Fig. 7-17) should allow the user's hand to remain behind the needle at all times, create a barrier between the hands of the user and the needle after use, be activated using a one-handed technique, and provide permanent (not temporary) containment of the needle. A needle safety feature should never be a temporary measure.

8. Lithium heparin is a suitable anticoagulant for which of the following tests? a. CBC b. Lytes c. Lithium d. Protime

8. Answer: b WHY: Lithium heparin causes the least interference in chemistry testing and is the most widely used anticoagulant for plasma and whole-blood chemistry tests. Heparinized plasma is often used for STAT chemistry tests and other rapid-response situations when a fast turnaround time (TAT) for chemistry tests is needed.

80. Which gel separator tube contains EDTA? a. EST b. PPT c. PST d. SST

80. Answer: b WHY: An EDTA tube that contains a separator gel is called a plasma preparation tube, or PPT. A plasma separator tube (PST) contains heparin and gel. A serum separator tube (SST) contains silica particles or clot activator and gel. There is no separator gel tube called an EST.

81. Which additive contains a substance that inhibits phagocytosis of bacteria by white blood cells? a. Silica (glass) clot activator b. Sodium or lithium heparin c. Sodium polyanethol sulfonate d. Thixotropic silicon barrier gel

81. Answer: c WHY: Sodium polyanethol sulfonate (SPS) is used in tubes for blood culture collection because in addition to being an anticoagulant, this additive is formulated to inhibit phagocytosis of bacteria by white blood cells. SPS reduces the action of a protein called complement that destroys bacteria, slows down phagocytosis (ingestion of bacteria by leukocytes), and reduces the activity of certain antibiotics. Heparin inhibits thrombin. Silica activates or enhances clotting. When a specimen is centrifuged, thixotropic gel becomes a physical barrier between the serum or plasma and the cells to prevent the cells from metabolizing substances in the serum or plasma.

82. Which type of test can potentially be affected by tissue thromboplastin contamination? a. Chemistry b. Coagulation c. Microbiology d. Serology

82. Answer: b WHY: Tissue thromboplastin affects coagulation tests the most because it is a substance found in tissue that activates the extrinsic coagulation pathway. Tissue thromboplastin is picked up by the needle as it penetrates the skin during venipuncture and is flushed into the first tube filled during ETS collection or mixed with blood collected in a syringe. Although it is no longer considered a significant problem for prothrombin time (PT) and partial thromboplastin time (PTT) tests unless the draw is difficult or involves a lot of needle manipulation, it may compromise results of other coagulation tests. Therefore, any time a coagulation test other than PT or PTT is the first or only tube collected, a few milliliters of blood should be drawn into a "discard" tube.

83. Which of the following tests would be most affected by carryover of K2EDTA? a. BUN b. Glucose c. Potassium d. Sodium

83. Answer: c WHY: K2EDTA contains potassium. (K is the chemical symbol for potassium, and K2EDTA is an abbreviation for dipotassium EDTA.) Carryover of potassium EDTA formulations into tubes for potassium testing has been known to significantly increase potassium levels in the specimen, causing erroneously elevated test results.

84. Carryover from which tube has a greater potential to negatively affect the specimen in the next tube drawn? a. Half-full nonadditive tube b. Overfilled gray-top tube c. Underfilled EDTA tube d. All of the above

84. Answer: c WHY: Lavender stoppers contain the anticoagulant EDTA. According to CLSI, carryover from an underfilled additive tube has a greater potential to negatively affect the test results in a subsequent tube. Carryover from a nonadditive tube would not affect the next tube. A gray-top tube is drawn last so there is no subsequent tube to affect.

85. A trace-element specimen tube should be collected a. after any other tubes. b. before any other tubes. c. separately or by syringe. d. with a 21-gauge butterfly.

85. Answer: c WHY: A needle can pick up contaminants going through tube stoppers. Trace elements are measured in such small quantities that these contaminants could affect test rests. Consequently, a trace-element tube should be collected separately or by syringe to prevent another stick if other tests are ordered. If a syringe is used the trace-element tube must be filled last after changing to a new transfer device.

86. A pink-top tube containing EDTA is primarily used for a. blood bank tests. b. chemistry tests. c. coagulation tests. d. microbiology tests.

86. Answer: a WHY: A pink-top EDTA tube typically has a special label for ID information and is used primarily for blood bank tests.

87. The blood collection equipment shown in Figure 7-1 can be used a. with a syringe-style technique. b. as an ETS. c. with a butterfly. d. in all of the above ways.

87. Answer: d WHY: The S-Monovette Blood Collection System (see Fig. 7-1) is a complete system for blood collection in which the blood collection tube and collection apparatus are combined in a single unit. The unit allows the specimen to be collected by either an evacuated tube system (ETS) or syringe system technique. The units are available with regular or butterfly-style needles.

88. Identify the tubes needed to collect a PT, STAT lytes, and BC in the proper order of collection. a. Gold, yellow, light blue b. Light blue, lavender, yellow c. SST, yellow, light blue d. Yellow, light blue, PST

88. Answer: d WHY: A prothrombin time (PT) is collected in a light blue-top tube, STAT electrolytes (lytes) require a green top or a PST, and a blood culture (BC), though usually collected in special bottles, is sometimes collected in a yellow-top SPS tube. The BC (yellow) is collected first because it requires a sterile collection site. The PT (light blue) is collected next, and the lytes (green or PST) are collected last.

89. Which of the following tubes is additive free? a. BD clear/red b. BD green/gray c. Vacuette blue d. Vacuette red

89. Answer: a WHY: A BD clear top or glass red-top tube has no additive. A plastic red-top tube has a clot activator. A plasma separator tube (PST) contains heparin and barrier gel. A serum separator tube (SST) has clot activator and barrier gel (Table 7-3).

9. Which additive is in some royal blue-top tubes? a. Citrate b. EDTA c. Fluoride d. Oxalate

9. Answer: b WHY: Royal blue-top tubes contain EDTA, heparin, or no additive to meet various test requirements. Tube labels are typically color coded to indicate the type of additive, if any, in the tube.

90. Which chemistry tube could contain either of two different forms of an anticoagulant because both have the same stopper color? a. Blue b. Gray c. Green d. Tan

90. Answer: c WHY: Green stopper color means the additive in the tube is heparin. Heparin is an anticoagulant that is available in ETS tubes in two forms, lithium heparin and sodium heparin. Each form has its own tube; however, both lithium heparin and sodium heparin tubes have green stoppers (see Table 7-3). Consequently, the phlebotomist must be careful in selecting the right tube for the ordered test because the two forms of heparin are not normally interchangeable.

91. Which additive can be found in four separate tubes with different stopper colors? a. EDTA b. Heparin c. Potassium oxalate d. Sodium citrate

91. Answer: a WHY: Lavender, pink, royal blue (lavender label), and BD tan tubes all contain the anticoagulant EDTA (see Table 7-3).

92. Which stopper color is the same for two completely different types of additives used by two different departments? a. Blue b. Green c. Tan d. Yellow

92. Answer: d WHY: The sodium polyanethol sulfonate (SPS) tube that is processed in the microbiology department has a yellow stopper, as does the tube containing acid citrate dextrose (ACD) that is used by the immunohematology department for DNA testing (see Table 7-3).

93. Most healthcare facilities have discontinued use of which type of glove due to allergic reactions? a. Latex b. Neoprene c. Polyethylene d. Vinyl

93. Answer: a WHY: Because of the prevalence of latex allergies in glove users and patients, most healthcare facilities have discontinued the use of latex gloves and other items made of latex (e.g., tourniquets). Gloves and other items made of alternative materials are readily available.

94. Which of the following additives is most commonly used for chemistry tests? a. ACD b. Citrate c. Heparin d. SPS

94. Answer: c WHY: Both lithium and sodium heparin are used by the chemistry department (see Table 7-3). Acid citrate dextrose (ACD) is used for certain immunohematology tests. Sodium citrate is most commonly used for coagulation tests. Sodium polyanethol sulfonate (SPS) is used for blood cultures which are microbiology tests.

95. An ETS holder and a syringe transfer device look very similar. What is the difference between the two? a. The hub on the transfer device attaches to a multisample needle or syringe barrel. b. The transfer device is smaller in size than the regular holder and has no flanges. c. There is a permanently attached needle with a sleeve inside the transfer device. d. There is no difference between the ETS holder and the syringe transfer device.

95. Answer: c WHY: A syringe transfer device (Fig. 7-18A) is similar to an ETS tube holder but has a permanently attached needle inside the holder. The needle with sleeve is the same as you would find on a multisample ETS needle. This allows the transfer device holder to be attached to a syringe and ETS tubes inserted, pierced by the needle inside the holder, and filled from the syringe (Fig. 7-18B).

96. A prothrombin time (PT) and platelet count are ordered on an 80-year-old female patient. Deciding to use a butterfly and "short draw" evacuated tubes on the tiny cephalic vein on the dorsal side of her right hand, the phlebotomist collects one light blue-top tube and then a lavender top. Why might the PT test results be incorrect and the platelet count unaffected? a. No tube was drawn to remove air in the butterfly tubing. b. PTs should never be collected using "short draw" tubes. c. The tubes were drawn in the wrong collection sequence. d. Venipuncture of the tiny vein led to specimen hemolysis.

96. Answer: a WHY: The first tube collected with a butterfly will underfill because of air in the tubing. If the tube contains an additive, underfilling will affect the blood-to-additive ratio. If a citrate tube is the first tube to be collected, it is important to draw a few milliliters of blood into a nonadditive tube or another additive tube of the same type, and discard it before collecting the first tube. This practice is referred to as collecting a "clear" or discard tube (Fig. 7-19) and is especially critical when collecting coagulation tests with a butterfly.

97. A home care phlebotomist had a requisition to collect a CBC, plasma K, PTT, and PT. He collected the tubes from the patient, who was lying on the sofa with her arm elevated above her shoulder on a table next to the sofa. As he collected the tests in the order of CBC, K, and finally the PT and PTT, he was careful to invert the tubes as specified. Later that day, the lab called the phlebotomist to say that three of the tests would have to be redrawn. Which three tests most likely had questionable results and needed to be redrawn? a. CBC, PT, and potassium b. Potassium, PTT, and PT c. PTT, potassium, and CBC d. PTT, PT, and CBC

97. Answer: b WHY: Tubes were drawn in the wrong order, and the patient's arm position during the venipuncture most likely allowed them to fill from the stopper end first. This allows blood in the tube to be in contact with the needle which can result in carryover of additive to the next tube filled. Since the lab asked for three of the tests to be redrawn, it is probable that potassium EDTA from the CBC tube carried over to the potassium (K) tube filled after it. Potassium is collected in a heparin tube. Heparin most likely carried from the potassium tube into the PT and PTT tube. Consequently, the potassium, PT and PTT would all be affected and need to be recollected.