Chapter 10: Capillary Puncture Equipment, Principles and Procedures

1. "Arterialized" means a. arterial content has been increased. b. composition is the same as arterial. c. oxygen levels equal arterial levels. d. venous blood flow has increased.

1. Answer: a WHY: "Arterialized" is a term used to describe a capillary blood specimen in which the arterial content has been increased by warming the site before collection. Warming changes the composition of a specimen because it increases blood flow into the area from the arteries. Although this specimen more closely resembles arterial blood than one that has not been warmed, oxygen levels and other components would still not be equal to arterial blood values.

10. Which of the following descriptions most accurately describes capillary puncture blood? a. A mix of venous, arterial, and capillary blood b. Mostly tissue fluid mixed with arterial blood c. Mostly venous blood mixed with tissue fluid d. Nearly identical to a venous blood specimen

10. Answer: a WHY: Capillary puncture blood is a mixture of arterial blood (from arterioles), venous blood (from venules), and capillary blood along with interstitial and intracellular fluids from the surrounding tissues.

100. Applying gentle intermittent pressure during a capillary puncture a. can hemolyze red cells. b. helps blood flow freely. c. is incorrect procedure. d. removes alcohol residue.

100. Answer: b WHY: Gentle pressure is correct procedure and is usually needed to keep the blood flowing during a capillary puncture. Gentle pressure should not hemolyze red blood cells, but strong pressure or squeezing the site could. Alcohol residue is removed by wiping away the first drop of blood.

11. All the following characteristics concerning microhematocrit tubes are correct EXCEPT that they are a. coated with lithium heparin. b. filled using capillary action. c. narrow-bore capillary tubes. d. used for PCV determination.

11. Answer: a WHY: Microhematocrit tubes are thin, narrow-bore, disposable plastic or plastic-clad glass tubes that fill by capillary action. They are most commonly used to collect and perform manual hematocrit (HCT) tests. An HCT is also called a packed cell volume (PCV) test. Some microhematocrit tubes are coated with ammonium heparin, not lithium heparin.

12. Referring to Figure 10-1, identify the letters of the fingers that are recommended as sites for capillary puncture. a. A and B b. B and C c. C and D d. D and E

12. Answer: c WHY: The fingers identified by letters C and D in Figure 10-1 are the middle and ring fingers, which are the recommended fingers to use for capillary puncture (Fig. 10-5).

13. Osteochondritis is a. abnormal bone formation and growth. b. an inherited bone metabolism disorder. c. infection of the bone and bone marrow. d. inflammation of the bone and cartilage.

13. Answer: d WHY: "Osteochondritis" means inflammation of the bone and cartilage. It can be the result of capillary punctures that are too deep.

14. Which is a term for the bottom surface of the heel? a. Distal b. Dorsal c. Lateral d. Plantar

14. Answer: d WHY: "Plantar" means concerning the sole or bottom of the foot. "Distal" means farthest from the center of the body, origin, or point of attachment. "Dorsal" means to the back of the body. "Lateral" means toward the side of the body.

15. Whorls as related to capillary puncture are a. blebs created during skin tests. b. formations seen in blood films. c. newborn screening blood spots. d. spiral patterns of fingerprints.

15. Answer: d WHY: Whorls are circular or spiral patterns formed by the lines of the fingerprint.

16. The temperature of heel warming devices should never exceed a. 37°C. b. 42°C. c. 98°F. d. 112°F.

16. Answer: b WHY: To prevent burning the patient, heel warmers and other materials used to warm the collection site before capillary puncture should provide a uniform temperature that does not exceed 42°C.

17. Which of the following is the medical term for a finger bone? a. Calcaneus b. Clavicle c. Patella d. Phalanx

17. Answer: d WHY: The medical term for a finger or toe bone is phalanx (plural, phalanges). "Calcaneus" is the medical term for heel bone. "Clavicle" is the medical term for the shoulder bone. "Patella" is the medical term for the kneecap.

18. CBG specimens are collected in a. amber syringe-style devices. b. bullets with heparin in them. c. circles on special filter paper. d. narrow-bore capillary tubes.

18. Answer: d WHY: Capillary blood gas (CBG) specimens are collected in special long, thin, narrow-bore plastic capillary tubes. They are generally 100 mm long with a capacity of 100 μL. They typically contain sodium heparin and are color-coded with a green band. Other equipment required includes a device to warm the site, stirrers and a magnet for mixing the specimen, and caps for both ends of the capillary tube so that the anaerobic condition of the specimen can be maintained. Capillary blood gas equipment is shown in Figure 10-6.

19. You have a request to collect a CBC, bilirubin, and electrolytes by capillary puncture on an infant. Which of the following shows the correct order of collection? a. Bilirubin, CBC, electrolytes b. CBC, electrolytes, bilirubin c. Electrolytes, bilirubin, CBC d. None of the above

19. Answer: b WHY: Puncturing the skin releases tissue thromboplastin, which activates the coagulation process in the blood drops. Unless capillary blood gases are ordered, hematology specimens (e.g., CBC) are collected first because they are most affected by the clotting process. Other additive specimens are collected next. Electrolytes are collected in a green-top tube that contains the anticoagulant heparin. Bilirubin tests are performed on serum. Serum microtubes are collected last because they are supposed to clot.

2. A blood smear is blood a. collected on a special filter paper. b. made from a heparinized specimen. c. spread out on a microscope slide. d. used to identify types of bacteria.

2. Answer: c WHY: A blood smear or film is a drop of blood spread on a glass microscope slide. Blood smears can be made from fresh blood or blood collected in EDTA, depending on the test requested. A manual differential is the most common reason a blood smear is made. A differential is used to identify and count the different types of cells in a blood smear. Blood collected on a special type of filter paper is required for most newborn screening tests.

20. Which numbered arrows on the diagram of an infant's foot in Figure 10-2 point toward the safest areas for capillary puncture? a. 1 and 4 b. 2 and 3 c. 3 and 5 d. 4 and 5

20. Answer: c WHY: According to Clinical and Laboratory Standards Institute (CLSI) standards, the safest areas for heel puncture are on the medial or lateral plantar surfaces of the heel. The safe areas on the heel are described as medial to an imaginary line extending from the middle of the great toe to the heel, or lateral to an imaginary line extending from between the fourth and fifth toes to the heel (Fig. 10-7). Punctures in other areas of an infant's foot risk bone, nerve, tendon, and cartilage injury.

21. Which of the following are required characteristics of capillary puncture lancets? a. A controlled depth of puncture b. Blades or points that are sterile c. Permanently retractable blades d. All of the above

21. Answer: d WHY: Capillary puncture lancets should be sterile and disposable after a single use. They should also have puncture depths that are controlled and blades or points that are permanently retractable for safety.

22. Which of the following equipment is used to collect a manual packed cell volume test? a. Circles on filter paper b. Glass microscope slide c. Microhematocrit tube d. Mixing bar and magnet

22. Answer: c WHY: A plastic or plastic-clad glass microhematocrit tube (Fig. 10-8) is used to collect and perform a manual hematocrit (packed cell volume) test.

23. All of the following are needed for capillary blood gas collection EXCEPT a. caps for both tube ends. b. filter paper for blotting. c. magnet and metal bar. d. plastic capillary tube.

23. Answer: b WHY: Capillary blood gas equipment (see Fig. 10-6) typically includes a special long, thin capillary tube, a magnet and a small metal bar to aid in mixing the specimen, and caps for sealing both ends of the tube. Blotting with filter paper is not part of the procedure.

24. Which capillary specimen should be collected separately? a. Bilirubin b. CBGs c. NBS d. Potassium

24. Answer: c WHY: According to CLSI standards, newborn screening (NBS) specimens should be collected separately. Except for NBS specimens, bilirubin, CBGs, and potassium specimens can be collected at the same time as other capillary specimens provided the capillary order of collection is followed. The order of collection for capillary specimens is capillary blood gases (CBGs), EDTA specimens, other additive specimens, and specimens requiring serum.

25. Which of the following is an indication for capillary puncture? a. The patient is badly burned except for his feet. b. The person is receiving IVs for chemotherapy. c. The physician requested capillary draws only. d. All of the above.

25. Answer: d WHY: Indications for capillary collection vary. Physicians may request that their patients have only capillary draws and a physician's orders must be followed. If a person is badly burned and the only available choice for blood collection is somewhere on the feet, capillary puncture on the toes will save the foot veins for other uses. Sometimes available veins are fragile or limited and must be reserved for critical procedures such as IV chemotherapy.

26. The composition of blood obtained by capillary puncture more closely resembles a. arterial blood. b. lymph fluid. c. tissue fluid. d. venous blood.

26. Answer: a WHY: Capillaries contain both venous and arterial blood. The percentage of arterial blood is higher, however, because arterial blood enters the capillaries under pressure. Consequently, the composition of blood obtained by capillary puncture more closely resembles arterial blood than venous blood. This is especially true if the area has been warmed, because warming increases arterial flow into the area.

27. If venous blood is placed in a microtube, it is important to a. label it as a venous specimen. b. shield the specimen from light. c. transport it to the laboratory ASAP. d. vigorously mix the specimen.

27. Answer: a WHY: Sometimes venous blood obtained by syringe during difficult draw situations is put into microcollection containers. When this is done, it is important to label the specimen as venous. Otherwise, it will be assumed to be a skin puncture specimen, which may have different normal values.

28. A laboratory report form should state that a specimen has been collected by capillary puncture a. for equipment inventory control purposes. b. because results can vary by specimen source. c. so other tests will be capillary collections. d. to satisfy liability insurance requirements.

28. Answer: b WHY: Test results can vary depending on the source of the specimen. A laboratory report form should indicate that a specimen was collected by capillary puncture, because capillary puncture blood differs in composition from venous blood and may have different reference ranges for some tests.

29. Blood collected by puncturing the skin is called capillary blood because a. it is collected with capillary tubes. b. it is from the capillaries in the skin. c. microtubes fill by capillary action. d. small drops of blood are collected.

29. Answer: b WHY: Blood obtained by puncturing the skin with a lancet is called capillary blood because it comes from the area of the dermis that is rich in capillaries that are part of the primary blood supply of the skin.

3. The calcaneus is a bone located in the a. earlobe. b. finger. c. heel. d. thumb.

3. Answer: c WHY: "Calcaneus" is the medical term for the heel bone. Finger bones, including the thumb, are called phalanges (singular, phalanx). The earlobe is cartilage, not bone.

30. Which test is typically performed on capillary blood? a. CBC b. GTT c. PKU d. PTT

30. Answer: c WHY: Phenylketonuria (PKU) is a newborn screening test. PKU and most other newborn screening tests were designed to be performed on capillary blood and are typically performed on capillary specimens collected by heel puncture. CBCs can be performed on capillary specimens but are most commonly performed on venipuncture specimens. Glucose tolerance tests (GTTs) are rarely performed on capillary specimens. PTTs are typically performed on venous specimens and are only performed on capillary specimens by using special point-of-care testing instruments.

31. Reference values for this test are higher for capillary specimens. a. Calcium b. Glucose c. Phosphorus d. Total protein

31. Answer: b WHY: Reference values for glucose tests are higher for capillary puncture specimens. They are lower for calcium, phosphorus, and total protein.

32. You need to collect blood cultures, and green-, light blue-, and purple-top tubes on an adult with difficult veins. Which of these can be collected by skin puncture? a. Blood cultures and green top b. Blood cultures and purple top c. Green top and purple top d. Light blue and purple top

32. Answer: c WHY: Blood cultures cannot be collected by capillary puncture because of the volume of blood required for testing and contamination issues. The light blue-top tube cannot be collected by capillary puncture because coagulation tests are greatly affected by tissue thromboplastin. Green-top and purple-top microtubes are available.

33. If collected by capillary puncture, which of the following specimens should be collected in an amber microtube (Fig. 10-3)? a. Bilirubin b. Glucose c. Lead d. PKU

33. Answer: a WHY: Infant bilirubin specimens are collected in amber microcollection containers (see Fig. 10-3) to help protect them from light. Light breaks down bilirubin and leads to false low values.

34. Situations that require a venipuncture instead of capillary puncture include when a a. bilirubin is ordered on a 1-year-old. b. glucose is ordered on a diabetic patient. c. K+ test using i-STAT is ordered in the ER. d. plasma protime specimen is ordered.

34. Answer: d WHY: A plasma protime is collected in a light blue-top tube. Light blue-top tubes cannot be collected by capillary puncture. Light blue-top capillary tubes are available from some manufacturers, but they are for other uses. There are, however, some point-of-care instruments that directly perform coagulation tests from capillary blood that is immediately placed in the instrument and tested.

35. Which of the following patient conditions would make capillary puncture a good choice for specimen collection? a. Acute dehydration b. Iatrogenic anemia c. Poor circulation d. State of shock

35. Answer: b WHY: Capillary puncture is generally not appropriate for patients who are dehydrated or have poor circulation to the extremities from other causes, such as a state of shock, because specimens may be hard to obtain and may not be representative of blood elsewhere in the body. Capillary puncture is actually a good choice for a patient with iatrogenic anemia so that as little blood as possible is removed.

36. Which of the following is normally a proper site for finger puncture on an adult? a. Distal segment of the middle finger b. End segment of either of the thumbs c. Medial segment of the index finger d. Proximal phalanx of the ring finger

36. Answer: a WHY: The palmar surface of the distal or end segment of the middle or ring finger (see Fig. 10-5) is the recommended site for routine skin puncture on an adult.

37. Capillary puncture is the preferred method to obtain blood from infants and children for all the following reasons EXCEPT a. restraining used for venipuncture can cause injury. b. results on capillary specimens are more accurate. c. they have small blood volumes compared with adults. d. venipuncture can damage their veins and tissues.

37. Answer: b WHY: Capillary puncture is the preferred method to obtain blood from infants and children for several reasons. Restraining methods used during venipuncture can injure infants and children. They have such small blood volumes that removing larger quantities of blood typical of venipuncture can lead to anemia. Removal of more than 10% of an infant's blood volume at one time can lead to cardiac arrest. In addition, venipuncture in infants and children is difficult and may damage veins and surrounding tissues. Test results on capillary specimens are not more accurate than results on venous specimens.

38. Which of the following sites would normally be eliminated as a capillary puncture site? a. Index finger of a woman b. Infant lateral plantar heel c. Middle finger of an adult d. Ring finger on an IV arm

38. Answer: a WHY: Under normal circumstances, capillary puncture should not be performed on an index finger. The index finger is usually more calloused and harder to poke. It is also more sensitive, so the puncture can be more painful, and because typically that finger is used more, a patient may notice the pain longer. Like venipuncture, a capillary puncture can be performed below an IV. The lateral plantar surface of an infant's heel and the middle or ring finger of an adult are recommended capillary puncture sites.

39. It is necessary to control the depth of lancet insertion during heel puncture to avoid a. damage to the tendons. b. injuring the calcaneus. c. puncturing an artery. d. unnecessary bleeding.

39. Answer: b WHY: The depth of lancet insertion must be controlled to avoid injuring the heel bone. The medical term for the heel bone is "calcaneus." Puncturing an artery or damaging tendons is avoided by puncturing in a recommended area. A deep puncture does not necessarily produce more bleeding.

4. The abbreviation for a pulmonary function test is a. AFP. b. CBG. c. PKU. d. TSH.

4. Answer: b WHY: Capillary blood gases (CBGs) are collected to assess levels of blood components, such as oxygen, carbon dioxide, and pH, which are measures of pulmonary function.

40. According to CLSI, depth of heel puncture should not exceed a. 1.5 mm. b. 2.0 mm. c. 2.4 mm. d. 4.9 mm.

40. Answer: b WHY: Studies have shown that heel punctures deeper than 2.0 mm risk injuring the calcaneus, or heel bone. For this reason, the latest Clinical and Laboratory Standards Institute (CLSI) capillary puncture standard states that heel puncture depth should not exceed 2.0 mm.

41. Which of the following can be a complication of a heel puncture that is too deep? a. Osteoarthritis b. Osteoporosis c. Osteomyelitis d. Osteosarcoma

41. Answer: c WHY: A deep heel puncture can penetrate the calcaneus (heel bone), leading to painful osteomyelitis (inflammation of the bone including the marrow) or osteochondritis (inflammation of the bone and cartilage).

42. Which of the following is the safest area of an infant's foot for capillary puncture? a. Any area of the arch b. Center of the big toe c. Medial plantar heel d. Posterior curvature

42. Answer: c WHY: According to CLSI, the safest areas for performing heel puncture are on the plantar surface of the heel, medial to an imaginary line extending from the middle of the great (big) toe to the heel, or lateral to an imaginary line extending from between the fourth and fifth toes to the heel (see Fig. 10-7). Thus, safe areas are on the medial or lateral plantar surface of the heel. Punctures should not be performed in the central portion of the heel or the posterior curvature of the heel because bone and cartilage injury can occur. All areas of the arch should be avoided because nerves and tendons can be injured. The big toe should not be punctured because it has an artery that could inadvertently be punctured.

43. A recommended capillary puncture site on children 2 years of age or older is on the a. bottom of an earlobe. b. fleshy side of a thumb. c. pad of a middle finger. d. medial or lateral heel.

43. Answer: c WHY: The recommended site for capillary puncture in older children and adults (see Fig. 10-5) is the pad (fleshy portion) of the palmar surface of the distal or end segment of a middle or ring finger.

44. In which of the following areas does capillary specimen collection differ from routine venipuncture for tests that can be collected either way? a. Additives used b. Antiseptic used c. ID procedures d. Order of draw

44. Answer: d WHY: Order of draw for microtubes is different from that of ETS tubes. Capillary puncture releases tissue thromboplastin, which activates the coagulation process and leads to platelet clumping and microclot formation in specimens that are not collected quickly. This affects hematology specimens the most; consequently, they are collected first unless CBGs are also ordered. (CBGs are always collected first, but they are not collected in microtubes.) Serum specimens are collected last because they are supposed to clot. In the order of draw for venipuncture, which was designed to minimize problems caused by additive carryover between tubes, serum specimens are collected before hematology specimens. Carryover is not an issue with capillary collection. Isopropyl alcohol is the recommended antiseptic for capillary puncture and routine venipuncture. Patient identification is the same regardless of the specimen collection method. Additives in microcollection tubes and stopper colors correspond to those of evacuated tubes.

45. The distance between the skin surface and the bone in the end segment of a finger is a. shortest at the side and the tip. b. equal throughout the fingertip. c. thickest of all in the fifth finger. d. thinnest in the middle finger.

45. Answer: a WHY: The distance between the skin surface and the bone in the end segment of the finger varies. It is less at the side and tip of the finger than at the center. It is thinnest in the fifth, or little, finger.

46. The blood vessels in a newborn's heel are located a. at the dermal-subcutaneous junction. b. between the epidermis and the dermis. c. in the epidermis and the subcutaneous. d. within the epidermis and the dermis.

46. Answer: a WHY: The major blood vessels of the skin are located at the dermal-subcutaneous junction, which in a newborn's heel is located between 0.35 and 1.6 mm below the surface of the skin (Fig. 10-9).

47. A capillary puncture that parallels the whorls of the fingerprint will a. allow blood to run down the finger. b. cause blood to form in round drops. c. continue to bleed for a lot longer. d. make specimen collection easier.

47. Answer: a WHY: If a capillary puncture is made parallel to the whorls of the fingerprint (see Fig. 10-5), blood will run down the grooves of the fingerprint rather than forming round drops that are easy to collect. It will not bleed longer.

48. A list of capillary puncture equipment would include all the following EXCEPT a. blood culture bottles. b. various lancet types. c. microcollection tubes. d. skin warming devices.

48. Answer: a WHY: Blood cultures cannot be collected by capillary puncture because of the large volume of blood required. In addition, capillary blood is exposed to the skin and the air during collection, which increases the possibility of contamination.

49. Which color-coded microtube would be used to collect a CBC? a. Gray b. Green c. Lavender d. Yellow

49. Answer: c WHY: A bullet with a lavender stopper contains EDTA, which is the additive used to collect complete blood counts (CBCs).

5. A cyanotic extremity would a. appear jaundiced. b. be bluish in color. c. exhibit erythema. d. look pale yellow.

5. Answer: b WHY: "Cyanotic" means marked by cyanosis or bluish in color from lack of oxygen; consequently, a cyanotic extremity looks bluish in color. Jaundiced skin would be a deep yellow color, and erythema indicates redness in the skin.

50. If the following tests are collected from a patient by capillary puncture, which test specimen is collected first? a. Bilirubin b. CBC c. Lytes d. Glucose

50. Answer: b WHY: A complete blood count (CBC) is a hematology test. When collected by capillary puncture, slides, platelet counts, and other hematology tests are collected first to avoid the effects of platelet aggregation (clumping) and microclot formation. Other anticoagulant containers are collected next, and serum specimens are collected last.

51. What is the purpose of warming the site before capillary puncture? a. Enhancing the visibility of veins b. Increasing the flow of blood c. Preventing sample hemolysis d. Relaxing and comforting patients

51. Answer: b WHY: Warming the site before capillary puncture increases blood flow up to seven times. Warming is said to arterialize the specimen because it increases arterial blood flow into the area. Enhancing visibility of veins is not necessary for capillary puncture. Hemolysis is mainly caused by squeezing the site, puncturing before the alcohol is dry, or using the first drop of blood instead of wiping it away; it can happen regardless of whether or not the site was warmed.

52. For accurate results, the heel must be warmed before collecting a capillary specimen for which test? a. CBG b. Lytes c. PKU d. WBC

52. Answer: a WHY: Warming the site for 5 to 10 minutes to increase arterial blood flow into the area is an important step in the collection of capillary blood gas (CBG) specimens. This arterializes the specimen, which means it increases the arterial content and makes it more like arterial blood. A towel or diaper dampened with warm tap water can be used to warm the site; however, care must be taken not to get the water too hot, or the patient may be scalded. Special warming devices (Fig. 10-10) that provide a uniform temperature that does not exceed 42°C are available. Warming the site before collecting other specimens is done to make collection easier, not for accuracy of results.

53. The recommended antiseptic for cleaning capillary puncture sites is a. 70% isopropanol. b. povidone-iodine. c. soap and water. d. tincture of iodine.

53. Answer: a WHY: CLSI recommends using 70% isopropyl alcohol (isopropanol or ETOH) to cleaning capillary puncture sites.

54. The antiseptic must be completely dried before performing capillary puncture to avoid a. hematoma formation. b. hemoconcentration. c. premature clotting. d. specimen hemolysis.

54. Answer: d WHY: The antiseptic used to clean a capillary puncture site is isopropyl alcohol. If the site is not completely dry before capillary puncture, alcohol residue can cause hemolysis of the specimen and lead to erroneous test results.

55. Tests affected by povidone-iodine contamination of a capillary specimen include a. phosphorus. b. potassium. c. uric acid. d. All of the above.

55. Answer: d WHY: Povidone-iodine contamination of capillary puncture blood has been shown to cause erroneous results for uric acid, phosphorus, and potassium tests.

56. Errors in capillary glucose results have been attributed to a. excessive depth of the capillary puncture. b. failure to collect the initial drop of blood. c. isopropanol contamination of the specimen. d. warming of the site before capillary puncture.

56. Answer: c WHY: Errors in glucose results have been attributed to isopropyl alcohol (isopropanol) contamination of the specimen. Deep punctures can injure bone but do not affect test results. The first drop of blood should be wiped away (see Fig. 10-4) to eliminate alcohol residue and tissue fluid contamination. Errors in glucose results have not been attributed to warming the site.

57. Proper finger puncture technique would include all the following EXCEPT a. choosing a middle or ring finger site. b. puncturing parallel to the fingerprint. c. trying not to squeeze or milk the site. d. warming the site before puncturing.

57. Answer: b WHY: Fingersticks should be made perpendicular to the whorls or grooves of the fingerprint (see Fig. 10-5 refer to #36) so that the blood forms round drops (Fig. 10-11) that can be collected easily. A puncture parallel to the whorls allows the blood to run down the finger and makes collection difficult.

58. Hemolysis of a capillary specimen can erroneously elevate results for which test? a. Cholesterol b. Hemoglobin c. Potassium d. RBC count

58. Answer: c WHY: Blood cells contain potassium. Residual alcohol can hemolyze blood cells, releasing potassium into the liquid portion of the specimen, erroneously elevating potassium results.

59. One purpose of wiping away the first drop of blood (Fig. 10-4) during capillary specimen collection is to a. avoid contamination with bacteria. b. reduce tissue fluid contamination. c. improve blood flow to the site. d. minimize platelet aggregation.

59. Answer: b WHY: It is important to wipe away the first drop of blood during capillary puncture (see Fig. 10-4) because excess tissue fluid that is typically found in the first drop can affect test results. Omitting the first drop from the sample also eliminates alcohol residue that can keep the blood from forming well-rounded drops, and hemolyze the specimen.

6. A differential test is unable to determine a. a platelet estimate. b. packed cell volume. c. red cell morphology. d. WBC characteristics.

6. Answer: b WHY: A differential determines the type and characteristics of WBCs, RBC morphology, and an estimate of the platelet count. Packed cell volume (PCV) is another name for hematocrit (HCT), which is part of a complete blood count (CBC) but not part of a differential.

60. Which of the following actions taken while filling microcollection tubes would be considered bad technique? a. Letting blood run down the tube's inside wall b. Scooping up blood as it runs down the finger c. Tapping the tube gently to settle the specimen d. Touching the tube's scoop to each blood drop

60. Answer: b WHY: Scooping or scraping up blood that runs down the finger is not a proper technique because it introduces contamination, activates platelets, and can cause hemolysis of the specimen. Correct technique includes touching the tube's scoop to the drop of blood (Fig. 10-12) and letting the blood run down the inside of the tube. An occasional gentle tap of the tube may be necessary to settle the blood to the bottom of the tube.

61. Which of the following incorrect techniques would be least likely to introduce excess tissue fluid into a capillary puncture specimen? a. Collecting the first drop b. Pressing hard on the site c. Squeezing the puncture d. Wiping the alcohol dry

61. Answer: d WHY: Collecting the first drop instead of wiping it away, pressing hard on the site, and squeezing the site can all introduce excess tissue fluid into the specimen and affect test results and can also cause hemolysis. Wiping the alcohol dry can contaminate the site and is not a recommended technique but does not affect the tissue fluid level in the specimen.

62. Which of the following can result in microclot formation in a specimen collected in an anticoagulant microtube? a. Mixing it too soon b. Mixing it forcefully c. Overfilling the tube d. Underfilling the tube

62. Answer: c WHY: Microtubes contain a proper amount of anticoagulant for the recommended fill level. If a microtube is overfilled, there is not enough anticoagulant for the increased volume of blood, which can result in the formation of microclots or complete clotting of the specimen. A specimen should be mixed as soon as possible after collection. Mixing a specimen forcefully can cause hemolysis. Underfilling a tube can result in excess anticoagulant for the volume of blood, which can cause distortion of the cells.

63. During multisample capillary specimen collection, blood smears and EDTA specimens are obtained before other specimens to minimize a. effects of platelet aggregation. b. hemolysis of red blood cells. c. specimen hemoconcentration. d. tissue fluid contamination.

63. Answer: a WHY: Blood smears and EDTA specimens are obtained before other specimens to minimize the effects of platelet aggregation (clumping). When tissue is disrupted by skin puncture, the coagulation process is set in motion and platelets start to aggregate (stick or clump together) and adhere to the site to seal off the injury. This can lead to erroneously low platelet counts. Platelets are evaluated and their numbers estimated as part of a differential performed on a blood smear. A platelet count is part of a complete blood count performed on an EDTA specimen.

64. A blood smear is required for which test? a. Manual differential b. Neonatal bilirubin c. Newborn screening d. Packed cell volume

64. Answer: a WHY: A manual differential is performed on a stained blood smear. A neonatal bilirubin test is typically performed on serum collected in an amber microtube or bullet. Most newborn screening tests involve the collection of blood in circles on special filter paper. A manual packed cell volume (PCV) or hematocrit (HCT) is collected in a microhematocrit tube.

65. An acceptable routine blood smear a. covers the entire slide. b. forms a bullet shape. c. has a feathered edge. d. looks short and thick.

65. Answer: c WHY: An acceptable smear (Fig. 10-13) will cover about one-half to three-fourths of the surface of the slide and have the appearance of a feather in that there will be a smooth gradient from thick to thin when held up to the light. The thinnest area of a properly made smear, often referred to as the "feather," is one-cell thick and is the most important area because that is where a differential is performed.

66. A blood smear prepared from an EDTA specimen should be made a. after the blood cells settle in the tube. b. at the time the specimen is collected. c. before the specimen has been mixed. d. within 1 hour of specimen collection.

66. Answer: d WHY: A blood smear prepared from an EDTA specimen should be made within 1 hour of collection to prevent cell distortion caused by prolonged contact with the anticoagulant.

67. When making a blood smear by hand using two glass slides, the typical angle required of the spreader slide is a. 15 degrees. b. 20 degrees. c. 30 degrees. d. 45 degrees.

67. Answer: c WHY: When a blood smear is prepared using the two-slide method, one slide holds the drop used to make the smear and a second slide, placed on the first slide at an angle of approximately 30 degrees (Fig. 10-14), is used to spread the drop of blood across the slide and create the blood film.

68. If the phlebotomist makes a blood smear that is too short, he or she should try again and a. decrease the angle of the spreader slide. b. increase the angle of the spreader slide. c. place a smaller blood drop on the slide. d. put more pressure on the spreader slide.

68. Answer: a WHY: Blood smears that are too long or too short are not acceptable. The length of a blood smear can be controlled by adjusting the angle of the spreader slide or the size of the drop of blood. If a smear is too short, decreasing the angle of the spreader slide or using a larger drop of blood on the next attempt should result in a longer smear. Exerting more pressure will only distort the smear. Increasing the angle of the spreader slide or using a smaller drop will make an even shorter smear.

69. It is unlikely that holes in a blood smear would be caused by a. low hemoglobin. b. dirt on the slide. c. high lipid level. d. smudged slide.

69. Answer: a WHY: Dirt or fingerprints on the slide and fat globules or lipids in the specimen can result in holes in a blood smear. Blood with a low hemoglobin level may be thin and require a smaller drop or adjustment of the pusher slide to create a proper smear, but it would not normally cause holes in a blood smear.

7. "Feather" is a term used to describe the appearance of a. a newborn screening blood spot. b. blood in a thick malaria smear. c. lipemia in a bilirubin specimen. d. the thinnest area of a blood film.

7. Answer: d WHY: A properly made routine blood film or smear shows a smooth transition from thick to thin. The thinnest area of the film is only one cell thick and is called the feather because of its appearance when held up to the light. The feather is the area where a manual differential is performed.

70. Collection of a thick blood smear may be requested to detect a. elevated bilirubin. b. hypothyroidism. c. malaria microbes. d. phenylketonuria.

70. Answer: c WHY: Malaria can be caused by any of four different species of microorganisms called plasmodia. It is diagnosed by detecting the presence of plasmodia organisms in a peripheral blood smear. Diagnosis typically requires the evaluation of both regular and thick blood smears. Presence of the organism is observed most frequently in a thick smear; however, identification of the species requires evaluation of a regular blood smear.

71. A premature 34-week gestation newborn weighing 2.1 kg needs to have blood drawn for special laboratory tests. What percentage of the total blood volume of this infant is represented by 10 mL? a. 2.5% b. 4.0% c. 5.5% d. 9.0%

71. Answer: b WHY: The total blood volume of infants, especially premature infants, is an important consideration when ordering tests. The amount needed for the test and amount the infant can safely lose should be calculated by the physician and the person doing the phlebotomy. According to Table 10-1 in the TEXTBOOK, a 10-mL blood draw from an infant born at 34 weeks' gestation and weighing 2.1 kg would represent 4% of the infant's entire blood volume. Although a 10-mL sample is considered an acceptable amount to draw from an adult, if this amount is drawn frequently from an infant, it could result in anemia and the need for a transfusion.

72. Which statement concerning capillary blood gases is untrue? a. They are less dangerous to collect than ABGs. b. Results are much more accurate than those of ABGs. c. Specimens contain venous and arterial blood. d. Collection exposes the blood specimen to air.

72. Answer: b WHY: Capillary blood gases (CBGs) are less dangerous to collect than arterial blood gases (ABGs). However, CBG results are not as accurate as ABG results because of the partial arterial composition of capillary blood and because the open system of collection temporarily exposes the specimen to air, which can affect test results.

73. An infant may require a blood transfusion if blood levels of which substance exceed 18 mg/dL? a. Bilirubin b. Carnitine c. Galactose d. Thyroxine

73. Answer: a WHY: Bilirubin can cross the blood-brain barrier in infants, accumulating to toxic levels that can cause permanent brain damage or even death. A transfusion may be needed if levels increase at a rate equal to or greater than 5 mg/dL per hour or when levels exceed 18 mg/dL.

74. Phenylketonuria is a a. disorder caused by excessive phenylalanine ingestion. b. contagious condition caused by lack of phenylalanine. c. genetic disorder involving phenylalanine metabolism. d. temporary condition caused by lack of phenylalanine.

74. Answer: c WHY: Phenylketonuria (PKU) is a hereditary (genetic) disorder caused by an inability to metabolize the amino acid phenylalanine. Patients with PKU lack the enzyme necessary to convert phenylalanine to tyrosine. Phenylalanine accumulates in the blood and can rise to toxic levels. PKU cannot be cured, but it can normally be treated with a diet low in phenylalanine. If left untreated or if not treated early on, PKU can lead to brain damage and mental deficiencies.

75. Which of the following is a neonatal screening test? a. Bilirubin b. GALT c. H&H d. WBC

75. Answer: b WHY: Newborn screening is the term used to describe testing of newborns for the presence of genetic diseases such as galactosemia (GALT). Bilirubin, hemoglobin and hematocrit (H&H), and white blood cell (WBC) counts may be performed on newborns but are not screening tests.

76. Falsely decreased bilirubin results can be caused by a. collecting the specimen 5 minutes late. b. failing to protect the specimen from light. c. puncturing the heel close to the calcaneus. d. using isopropyl alcohol to clean the site.

76. Answer: b WHY: Bilirubin is broken down in the presence of light. Collecting the specimen too slowly or failing to protect the specimen from light after collection allows the specimen to be exposed to light for longer than necessary and leads to falsely decreased results.

77. Which of the following is least likely to contaminate a PKU test? a. Neglecting to discard the first blood drop b. Touching the inside of a filter paper circle c. Stacking specimen slips while wet or dry d. Using isopropyl alcohol to clean the site

77. Answer: d WHY: Isopropyl alcohol is the recommended antiseptic for cleaning prior to capillary puncture, including heel punctures performed to collect PKU specimens. If proper technique is used (i.e., the alcohol is allowed to dry before puncture and the first drop of blood is wiped away) alcohol contamination is unlikely to be an issue. PKU specimens are collected by placing large drops of blood within circles on special filter paper that is typically part of the test requisition (Fig. 10-15). Using the first drop of blood can contaminate an entire blood spot with tissue fluid and lead to erroneous results. Blood spots can also be contaminated by touching the circles with hands (with or without gloves) before, during, or after specimen collection. Stacking filter paper requisitions together after collection can lead to cross-contamination between different patient specimens.

78. Correct newborn screening test collection or handling includes a. applying blood drops to both sides of the filter paper. b. hanging a specimen slip to dry in a vertical position. c. layering successive blood drops in a collection circle. d. using one large drop to entirely fill a collection circle.

78. Answer: d WHY: Newborn screening blood spots must be collected properly to prevent erroneous results. Applying blood to both sides of the filter paper or layering successive drops in the same circle increases the amount of blood in the test area and can lead to erroneously increased results. Hanging specimens to dry can cause the blood to migrate and concentrate toward the lower end of the filter paper. This leaves the upper areas of the circle with less blood and the lower areas with more blood than required for testing. In this case, the results will be erroneous on any area that is used for testing. Letting one large drop of blood entirely fill a circle (Fig. 10-16) is correct procedure.

79. Neonatal screening for which disorder is required by law in the United States? a. Diabetes b. HDN c. HBV d. PKU

79. Answer: d WHY: Newborn screening to detect PKU, galactosemia (GALT), and hypothyroidism is required by law in all 50 states in the United States.

8. Fluid in the spaces between the cells is called a. interstitial fluid. b. intracellular fluid. c. lymphatic fluid. d. peritoneal fluid.

8. Answer: a WHY: "Interstitial" means pertaining to spaces between tissues; consequently, fluid in the spaces between the cells is called interstitial fluid. Intracellular fluid is the fluid within cells. Fluid in the lymphatic system is called lymph. Lymph is derived from excess tissue fluid and is similar to but not the same as interstitial fluid. Peritoneal fluid is found in the abdominal cavity.

80. Jaundice in a newborn is associated with high levels of a. bilirubin. b. glucose. c. ketones. d. thyroxine.

80. Answer: a WHY: High levels of bilirubin in the blood result in jaundice, a condition characterized by yellow color of the skin, whites of the eyes, mucous membranes, and body fluids.

81. It is inappropriate to apply a bandage to a capillary puncture site on an infant or child younger than 2 years of age because it can a. irritate an infant's tender skin. b. pull off and be a choking hazard. c. tear delicate skin when removed. d. All of the above.

81. Answer: d WHY: Adhesive bandages can irritate the tender skin of infants, come off and become a choking hazard, or tear the skin when removed. Consequently, they should not be used on infants or children younger than 2 years.

82. Which of the following action words associated with capillary puncture procedure steps are in the correct order? a. Clean, puncture, warm, wipe, and collect b. Clean, warm, puncture, collect, and wipe c. Warm, clean, puncture, wipe, and collect d. Warm, puncture, clean, wipe, and collect

82. Answer: c WHY: Heel puncture includes the following steps: (1) warm the site; (2) clean the site; (3) puncture the site; (4) wipe away the first blood drop; and (5) collect the specimen.

83. The best way to mix blood in an additive microtube is to a. invert it gently. b. shake it briskly. c. tap it sharply. d. All the above.

83. Answer: a WHY: Capillary specimens should be handled gently just like venous blood specimens. After capping, gentle inversions are required to adequately mix an anticoagulant microtube without hemolyzing red blood cells. Tapping the tube gently on a hard surface can be used to settle blood to the bottom of the tube during collection but is not adequate to mix the specimen. Tapping sharply can hemolyze the specimen.

84. Strong repetitive pressure, such as squeezing or milking a site during capillary specimen collection a. is necessary to obtain adequate blood flow. b. can hemolyze and contaminate specimens. c. improves the accuracy of CBC test results. d. increases venous blood flow into the area.

84. Answer: b WHY: Strong repetitive pressure such as squeezing or milking the site can contaminate a capillary specimen with excess tissue fluid, hemolyze the red blood cells, and compromise test results. If adequate blood flow cannot be obtained without such action, a new puncture should be made at a different site. Venous blood flows out of the area, not into it.

85. Which of the following collection devices fill by capillary action? a. Amber microtubes b. Filter paper circles c. Hematocrit tubes d. Lavender bullets

85. Answer: c WHY: Hematocrit tubes fill automatically when in contact with a drop of blood (Fig. 10-17) because of a force called capillary action or attraction. Blood drops must be absorbed onto filter paper circles for newborn screening tests and dripped into microtubes or bullets regardless of the type or stopper color.

86. Capillary puncture is preferred for infants because a. all infant laboratory tests require capillary collection. b. capillary blood results are more accurate. c. it is less painful to infants than a venipuncture. d. venipuncture can damage the veins of infants.

86. Answer: d WHY: Capillary puncture is preferred for infants because venipuncture can cause damage to their tiny veins and the tissue around the vein. This is especially true if the vein is difficult to access or is punctured too frequently. Tests performed in the laboratory for infants are the same as for adults and the results from capillary collection are often not as accurate as venous specimens. Capillary puncture is not necessarily less painful than venipuncture.

87. Lancets with permanently retractable blades are disposed of in the a. autoclave waste. b. biohazard trash. c. sharps container. d. regular trash can.

87. Answer: c WHY: Used lancets must be disposed of in a sharps container even though the blades are permanently retractable.

88. Capillary puncture is a poor choice for specimen collection if the patient is a. comatose. b. dehydrated. c. jaundiced. d. nauseated.

88. Answer: b WHY: Capillary puncture is generally not appropriate for patients who are dehydrated because specimens may be hard to obtain and results may not be representative of blood elsewhere in the body.

89. Which of the following steps should be omitted from infant heel puncture? a. Apply bandage. b. Clean the site. c. ID the patient. d. Warm the site.

89. Answer: a WHY: A bandage should not be applied to an infant or child younger than 2 years because it can pose a choking hazard. In addition, bandage adhesive can stick to the paper-thin skin of newborns and tear it when removed.

9. What is the name of a sharp-pointed device used today to make capillary punctures? a. Bullet b. Fleam c. Lancet d. Scalpel

9. Answer: c WHY: The typical lancet is a sterile, disposable, sharp-pointed, or bladed device used to puncture or make an incision in the skin to obtain a capillary blood specimen. A microcollection container is sometimes called a bullet because it resembles one. A fleam is the historical name for a type of lancet used in the 17th and 18th centuries. A scalpel should never be used for capillary puncture because puncture depth cannot be controlled.

90. After making a blood smear, a. blow on it until dry. b. let it dry naturally. c. place it in alcohol. d. wave it until dry.

90. Answer: b WHY: A blood smear must be allowed to air dry naturally. Blowing on it or waving it dries it too quickly, which can distort red blood cells and introduce contaminants. A blood smear should not be placed in alcohol before it is stained.

91. All of the following tests can be collected by capillary puncture EXCEPT a. blood culture. b. electrolytes. c. hemoglobin. d. lithium level.

91. Answer: a WHY: Blood cultures cannot be collected by capillary puncture because the volume of blood required for the tests is too large and the open collection method increases the possibility of contamination. Electrolytes, hemoglobin, and lithium levels can all be collected by capillary puncture.

92. Neonatal screening is the testing of a. babies for contagious diseases. b. infants with certain symptoms. c. newborns for certain disorders. d. pregnant women for diseases.

92. Answer: c WHY: Neonatal screening is the routine testing of newborns (neonates) for the presence of certain genetic (inherited), metabolic, hormonal, and functional disorders that can cause severe mental handicaps or other serious abnormalities if not detected and treated early. The disorders are not contagious and do not normally show symptoms at birth.

93. Microhematocrit tubes with a red band on one end contain a. EDTA. b. heparin. c. nothing. d. silica.

93. Answer: b WHY: Most microhematocrit tubes are either plain, meaning they have no additive, or are coated with ammonium heparin. Color-coding does not correspond to ETS tubes or microtubes. Nonadditive microhematocrit tubes have a blue band on one end; those containing heparin have a red band on one end.

94. In an infant's heel, the area of the vascular bed that is rich in capillary loops is located a. between 0.35 and 1.6 mm deep. b. from 1.00 mm to 2.00 mm deep. c. in the top layer of the epidermis. d. starting at around 2.4 mm deep.

94. Answer: a WHY: The area of an infant's heel that is richest in capillary loops is in the dermis between 0.35 and 1.6 mm deep (see Fig. 10-9).

95. Which of the following capillary puncture techniques is incorrect? a. Discard equipment packaging in the regular trash. b. Position the site downward to promote blood flow. c. Press the lancet down into the skin so it does not slip. d. Tap microtubes gently to settle blood to the bottom.

95. Answer: c WHY: Use only enough pressure to keep the lancet firmly against the skin. Pressing down hard on the lancet compresses the skin and can result in a deeper puncture than intended.

96. Pain receptors are located below a. 0.8 mm. b. 1.6 mm. c. 2.0 mm. d. 2.4 mm.

96. Answer: d WHY: The cross-section of a full-term infant's heel (see Fig. 10-9) shows that the pain receptors begin to appear in the subcutaneous layer just below the dermis. Consequently, deeper punctures activate more pain receptors.

97. Neonatal screening for this disorder is required by law in all 50 states. a. Galactosemia b. Hypothyroidism c. Phenylketonuria d. All of the above

97. Answer: d WHY: Newborn/neonatal screening is the state-mandated testing of newborns for the presence of certain genetic (inherited), metabolic, hormonal, and functional disorders that can cause severe abnormalities if not detected and treated early. Screening for phenylketonuria (PKU), galactosemia, and hypothyroidism is required by law in all 50 states and U.S. territories.

98. Capillary action is a term used to describe how a. arterial blood enters the capillaries. b. blood fills a microhematocrit tube. c. cells spread across a blood smear. d. warming can increase blood flow.

98. Answer: b WHY: The ability of a liquid to be automatically drawn into a narrow space or tube is called capillary action. If a microhematocrit tube is held in a vertical position above or in a horizontal position beside a blood drop and one end touched to the blood drop, blood will be automatically drawn into it by capillary action.

99. Which is an inherited amino acid metabolism disorder? a. GALT b. Hb SS c. MSUD d. All of the above

99. Answer: c WHY: Maple syrup urine disease (MSUD) is an inherited amino acid metabolism disorder. GALT (classic galactosemia) is a rare genetic disease that involves the inability to metabolize the milk sugar galactose. Hb SS (sickle cell anemia) is a hemoglobinopathy, an inherited disease that involves abnormal hemoglobin structure.