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Exercises for Lesson 6

1. When blood is centrifuged, the volume percentage occupied by the packed red cells is known as the:

a. Erythrocyte sedimentation rate (ESR).

b. Hematocrit.

c. Hemoglobin concentration.

d. Mean corpuscular volume.

2. The procedure for determining hematocrit is performed by:

a. Filling a capillary tube capillary with blood.

b. Centrifuging at constant speed for a constant period of time.

c. Measuring the packed-cell volume.

d. Automated sequential analyzers (the results are usually a calculated value).

e. All of the above.

3. The hematocrit is the most useful single index in determining the degree of:

a. Anemia.

b. Hypochromia or anemia.

c. Leukopenia.

d. Thrombocytopenia or thrombocytosis.

a. 1 to 3 percent.

b. 6 to 15 percent.

c. 2 to 4 percent.

d. 3 to 6 percent.

5. In contrast to hematological determinations, what is the percent error rate for the direct red blood cell chamber count?

a. 2 to 4 percent.

b. 5 to 9 percent.

c. 6 to 8 percent.

d. 8 to 10 percent.

6. The hematocrit values closely parallel the values for the:

a. Packed WBCs and hemoglobin.

b. Packed-cell blood count and reagent.

c. WBC count and hemoglobin.

d. Hemoglobin and RBC count.

a. A capillary tube is filled with plasma by capillary action to within 1 to 2 cm of the end. The unfilled end is sealed and the tube is centrifuged. After centrifugation, the capillary tube is placed in a reading device and the hematocrit value determined.

b. A capillary tube is filled with whole blood by capillary action to within 1 to 2 cm of the end. The unfilled end is sealed and the tube is centrifuged. After centrifugation, the capillary tube is placed in a reading device and the hematocrit value determined.

c. A capillary tube is filled with whole blood by capillary action to within 2 to 4 cm of the end. The unfilled end is sealed and the tube is centrifuged. After centrifugation, the capillary tube is placed in a reading device and the hematocrit value determined.

d. A capillary tube is filled with whole blood by capillary action to within 1 to 2 cm of the end. The filled end is sealed and the tube is centrifuged. After centrifugation, the capillary tube is read and recorded.

8. Centrifugation for the microhematocrit lasts:

a. 30 seconds.

b. 30 minutes.

c. 1 minute.

d. 5 minute.

9. During the microhematocrit test, blood without anticoagulant is identified by a heparinized capillary tube with a _____ line.

a. Green.

b. Red.

c. Yellow.

d. Pink.

a. One forth.

b. Halfway.

c. Three fourths.

d. Completely.

11. Measuring the microhematocrit test, when blood is allowed to enter the two capillary tubes to approximately 2/3 full and air bubbles appear, what does this signify?

a. A poor technique was used but it does not affect the results of the test.

b. The heparinized capillary tube line was passed.

c. The tubes were dirty.

d. The seal was broken.

12. At what rpm and for how long are the two hematocrit tubes centrifuged for the microhematocrit test?

a. 4,000 rpm; 2 minutes.

b. 5,000 rpm; 4 minutes.

c. 10,000 rpm; 5 minutes.

d. 15,000 rpm; 7 minutes.

a. +1 ;nothing.

b. +15; nothing.

c. +1; repeat the procedure.

d. +5; repeat the procedure.

14. Slanting of the cell layer in a microhematrocrit tube will occur if tubes are left in a _____ position for more than _____ minutes.

a. upright; 10.

b. vertical; 60.

c. horizontal; 45.

d. vertical; 30.

15. The rate at which red blood cells fall when anticoagulated whole blood is allowed to stand is known as:

a. Plasma composition.

b. Erythrocyte sedimentation.

c. Coulter models.

d. Spherocytosis.

16. Erythrocyte sedimentation is retarded when the hematocrit exceeds:

a. 35 percent.

b. 40 percent.

c. 45 percent.

d. 55 percent.

a. 38-47 percent and 34-41 percent.

b. 44-64 percent and 34-41 percent.

c. 44-64 percent and 40-54 percent.

d. 40-52 percent and 36-48 percent.

18. Size and shape of the erythrocytes cause the erythrocyte sedimentation rate (ESR) to:

a. Increase.

b. Remain the same.

c. Decrease.

d. Fluctuate.

19. During erythrocyte sedimentation and with certain diseases, what kind of formation may form in the plasma protein if the plasma protein fibrinogen and globulin are altered?

a. Round.

b. Spiral.

c. Rouleaux.

d. Short.

20. What happens to the mass of plasma and to the sedimentation rate when the plasma protein of fibrinogen and globulin are altered?

a. Mass enlarges; rate increases.

b. Mass decreases; rate decreases.

c. Mass shrivels; rate increases.

d. Mass enlarges; rate decreases.

a. A tilt of 50 can cause errors up to 55 percent.

b. A tilt of 30 can cause errors up to 30 percent.

c. A tilt of 10 can cause errors up to o. 05 percent.

d. There are no other factors that affect the ESR tube.

22. What other mechanical and technical factors are important and why when working with the ESR tube or holding rack?

a. Spilling the ESR tube or tilting holding rack can affect the ESR, as can extreme changes in temperature.

b. Static electricity or movement of the ESR tube or holding rack can affect the ESR, as can extreme changes in temperature.

c. Vibration or movement of the ESR tube or holding rack can affect the ESR as can extreme changes in temperature.

d. There are no other factors.

23. When determining the ESR, using the Wintrobe-Landsberg method, what happens to the anticoagulated blood and how is this procedure measured?

a. The anticoagulated blood is placed in a narrow tube.

b. The blood cells settle out of the suspension, leaving clear plasma above them.

c. The distance that the erythrocytes fall within a given interval of time is measured.

d. a, b, and c all happen.

e. a and d happen.

f. None of the above.

a. Green top vacuum tube.

b. Lavender top vacuum tube.

c. Red lined tube.

d. Blue lined tube.

25. After the Wintrobe tube is placed in a rack in an exactly vertical position and the time and room temperature are noted, when is a reading taken and what is observed?

a. At the end of exactly 1 hour, read the level to which the red cells have settled on the descending scale etched on the tube.

b. At the end of exactly 2 hour, read the level to which the red cells have settled on the descending scale etched on the tube.

c. Within 15 minute, read the level to which the red cells have settled on the ascending scale etched on the tube.

d. In 5 minutes, read the level to which the red cells have settled on the descending scale etched on the tube.

26. If measurement of the ESR is delayed more than 2 hours after blood collection, the reading may be inaccurate because of a:

a. False varied sedimentation rate.

b. False low sedimentation on rate.

c. False high sedimentation rate.

d. Varied sedimentation rate.

a. 0, 30 degrees.

b. 0, 45 degrees.

c. 5, 10 degrees.

d. 10, 50 degrees.

28. If the tube is at a 30 variation from vertical this is a source of error and will accelerate the ESR by _____ percent.

a. 30.

b. 70.

c. 40.

d. 50.

29. When using the modified Westergren method, whole blood is diluted with _____ percent saline and mixed for _____ minutes.

a. 0.85, 2.

b. 0.90, 3.

c.0.95, 4.

d. 0.80, 2.

30. Using the modified Westergren method, what is the normal value ESR for children?

a. 0-15 mm/hr.

b. 0-20 mm/hr.

c. 0-10 mm/hr.

d. 0-25 mm/hr.

a. Methemoglobin.

b. Carboxyhemoglobin.

c. Cyanmethemoglobin.

d. Reduced hemoglobin.

32. Hemoglobin reacts with oxygen to form:

a. Oxyhemoglobin.

b. Methemoglobin.

c. Cyanmethemoglobin.

d. Carboxyhemoglobin.

33. Which compound results when methemoglobin combines with the cyanide radical?

a. Oxyhemoglobin.

b. Sulfhemogobin.

c. Cyanmethemoglobin.

d. Carboxyhemoglobin.

34. As ferrous iron in hemoglobin is oxidized to the ferric state, which of the following is produced?

a. Methemoglobin.

b. Carboxyhemoglobin.

c. Carbaminohemglobin.

d. Reduced hemoglobin.

a. Hemoglobin F.

b. Hemoglobin A2.

c. Hemoglobin A.

d. Hemoglobin S.

36. Which is normally present in infants of less than 6 months but not normally present in adults?

a. Hemoglobin A.

b. Hemoglobin A2.

c. Hemoglobin F.

d. Hemoglobin S.

37. When hemoglobin combines with oxygen, its iron must be in what state?

a. Ferrous.

b. Globulin.

c. Anemic.

d. Active.

38. How many basic ways are there to measure the hemoglobin concentration?

a. 2.

b. 3.

c.4.

d. 5.

a. Gasometric.

b. Cyanmethemoglobin.

c. Chemical.

d. Specific gravity.

40. What does the spectrophotometer's 540 mm wavelength measure during the hemoglobin reaction using the cyanmethemoglobin method?

a. Specific gravity.

b. Proportionalism.

c. Color intensity.

d. Concentration.

41. Although the cyanmethemoglobin method is accurate, what is a disadvantage of using it?

a. It is not the most direct method.

b. If the cyanide compounds are handled incorrectly, they can be hazardous.

c. Venous samples give erratic values.

d. Its hemoglobin pigments are not stable.

42. The normal concentration of hemoglobin in blood of the adult male is:

a. 10-15 g/dL.

b. 12-16 g/dL.

c. 13-18 g/dL.

d. 18-27 g/dL.

a. SS cells.

b. SC cells.

c. SD cells.

d. a, b, and c.

e. a and c.

44. Erythrocytes of persons with sickle cell anemia or trait will assume a sickle shape when:

a. The oxygen tension is lowered.

b. The oxygen tension is raised.

c. An electrophoretic pattern is run.

d. Highly oxygenated blood is observed.

45. Sickle cell anemia is caused by:

a. Endocrine disorders.

b. Massive hemorrhage.

c. Chronic hemorrhage.

d. An inherited protein abnormality of hemoglobin.

46. Sickledex reagent is:

a. Totally stable.

b. Very stable.

c. Not stable after 20 days.

d. Stable for 60 days.

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