Success in CLS Ch. 3 Hemostasis (75 questions and
answers)
1. The hemorrhagic problems associated with scurvy are due to a deficiency of
________, which is a cofactor required for collagen synthesis.
A. Vitamin C
B. Prothrombin
C. Vitamin K
D. Protein C
A. Vitamin C
2. The number of platelets an average megakaryocyte generates is approximately
A. 25-50
B. 50-200
C. 200-500
D. 2000-4000
D. 2000-4000
3. Which of the following is not a cause of thrombocytopenia?
A. Splenomegaly
B. Chemotherapy
C. Increased thrombopoietin
D. Aplastic anemia
C. Increased thrombopoietin
4. Platelets interacting with and binding to other platelets is referred to as
A. Adhesion
B. Aggregation
C. Release
D. Retraction
B. Aggregation
5. In platelet aggregation studies, certain aggregating agents induce a biphasic
aggregation curve. This second phase of aggregation is directly related to
A. Formation of fibrin
B. Changes in platelet shape
C. Release of endogenous ADP
D. Release of platelet factor 3
C. Release of endogenous ADP
6. A platelet aggregation agent that characteristically yields a biphasic curve when used
in optimal concentration is
A. Arachidonic acid
B. Collagen
,C. Epinephrine
D. Ristocetin
C. Epinephrine
7. The platelet aggregation pattern drawn below is characteristic of the aggregating
agent (see picture in book)
A. ADP
B. Collagen
C. Ristocetin
D. Thrombin
B. Collagen
8 The operating principle of a platelet aggregometer is best described as
A. Aggregation on a foreign surface:
Platelet aggregation is directly proportional to the difference in platelet counts performed
before and after platelet-rich plasma is passed through a column of glass beads.
B. Change in optical density: As platelets aggregate, the optical density of the platelet-
rich plasma decreases.
C. Electrical impedance: Platelet aggregates are counted as they pass through an
aperture, temporarily interrupting the flow of current between two electrodes.
D. Pulse editing: Editing electronically generated pulses can differentiate the number of
free platelets versus platelet aggregates.
B. Change in optical density: As platelets aggregate, the optical density of the platelet-
rich plasma decreases.
9. Of the following therapeutic agents, those considered to be antiplatelet medications
are
A. Aspirin and Plavix®
B. Coumadin®andheparin
C. Heparin and protamine sulfate
D. Tissue plasminogen activator and
streptokinase
A. Aspirin and Plavix®
10. A potent inhibitor of platelet aggregation released by endothelial cells is
A. Epinephrine
B. Prostacyclin
C. Ristocetin
D. Thromboxane A2
B. Prostacyclin
11. The reference value for mean platelet volume (MPV) is approximately
A. 2-4 fL
B. 5-7fL
C. 8-10 fL
D. 11-14fL
, C. 8-10 fL
12. The platelet parameter PDW refers to the
A. Average platelet volume
B. Cell weight versus density
C. Capacity to adhere to foreign surfaces
D. Variation in platelet cell size
D. Variation in platelet cell size
13. A normal histogram showing platelet size distribution is best described as
A. Bimodal, nonskewed peaks
B. Left-skewed single peak
C. Right-skewed single peak
D. Single peak, Gaussian distribution
C. Right-skewed single peak
14. Which of the following is not a normal maturation stage for platelets?
A. Megakaryoblast
B. Promegakaryocyte
C. Micromegakaryocyte
D. Megakaryocyte
C. Micromegakaryocyte
15. The recommended type of microscopy for the performance of manual platelet
counts is
A. Electron
B. Darkfield
C. Light
D. Phase contrast
D. Phase contrast
16. Twenty microliters of blood are diluted in 1.98 mL of diluent. This dilution is plated
on both sides of a Neubauer-ruled counting chamber. A total of 356 cells is seen when
both large center squares are counted. The platelet count expressed in SI units is
A. 178xl09/L
B. 178xl03/|xL
C. 356xl09/L
D. 712xl09/L
A. 178xl09/L
17. The size threshold range used by electrical impedance methods to count particles
as platelets is
A. 0-10 fL
B. 2-20fL
C. 15-40fL
D. 35-90fL
answers)
1. The hemorrhagic problems associated with scurvy are due to a deficiency of
________, which is a cofactor required for collagen synthesis.
A. Vitamin C
B. Prothrombin
C. Vitamin K
D. Protein C
A. Vitamin C
2. The number of platelets an average megakaryocyte generates is approximately
A. 25-50
B. 50-200
C. 200-500
D. 2000-4000
D. 2000-4000
3. Which of the following is not a cause of thrombocytopenia?
A. Splenomegaly
B. Chemotherapy
C. Increased thrombopoietin
D. Aplastic anemia
C. Increased thrombopoietin
4. Platelets interacting with and binding to other platelets is referred to as
A. Adhesion
B. Aggregation
C. Release
D. Retraction
B. Aggregation
5. In platelet aggregation studies, certain aggregating agents induce a biphasic
aggregation curve. This second phase of aggregation is directly related to
A. Formation of fibrin
B. Changes in platelet shape
C. Release of endogenous ADP
D. Release of platelet factor 3
C. Release of endogenous ADP
6. A platelet aggregation agent that characteristically yields a biphasic curve when used
in optimal concentration is
A. Arachidonic acid
B. Collagen
,C. Epinephrine
D. Ristocetin
C. Epinephrine
7. The platelet aggregation pattern drawn below is characteristic of the aggregating
agent (see picture in book)
A. ADP
B. Collagen
C. Ristocetin
D. Thrombin
B. Collagen
8 The operating principle of a platelet aggregometer is best described as
A. Aggregation on a foreign surface:
Platelet aggregation is directly proportional to the difference in platelet counts performed
before and after platelet-rich plasma is passed through a column of glass beads.
B. Change in optical density: As platelets aggregate, the optical density of the platelet-
rich plasma decreases.
C. Electrical impedance: Platelet aggregates are counted as they pass through an
aperture, temporarily interrupting the flow of current between two electrodes.
D. Pulse editing: Editing electronically generated pulses can differentiate the number of
free platelets versus platelet aggregates.
B. Change in optical density: As platelets aggregate, the optical density of the platelet-
rich plasma decreases.
9. Of the following therapeutic agents, those considered to be antiplatelet medications
are
A. Aspirin and Plavix®
B. Coumadin®andheparin
C. Heparin and protamine sulfate
D. Tissue plasminogen activator and
streptokinase
A. Aspirin and Plavix®
10. A potent inhibitor of platelet aggregation released by endothelial cells is
A. Epinephrine
B. Prostacyclin
C. Ristocetin
D. Thromboxane A2
B. Prostacyclin
11. The reference value for mean platelet volume (MPV) is approximately
A. 2-4 fL
B. 5-7fL
C. 8-10 fL
D. 11-14fL
, C. 8-10 fL
12. The platelet parameter PDW refers to the
A. Average platelet volume
B. Cell weight versus density
C. Capacity to adhere to foreign surfaces
D. Variation in platelet cell size
D. Variation in platelet cell size
13. A normal histogram showing platelet size distribution is best described as
A. Bimodal, nonskewed peaks
B. Left-skewed single peak
C. Right-skewed single peak
D. Single peak, Gaussian distribution
C. Right-skewed single peak
14. Which of the following is not a normal maturation stage for platelets?
A. Megakaryoblast
B. Promegakaryocyte
C. Micromegakaryocyte
D. Megakaryocyte
C. Micromegakaryocyte
15. The recommended type of microscopy for the performance of manual platelet
counts is
A. Electron
B. Darkfield
C. Light
D. Phase contrast
D. Phase contrast
16. Twenty microliters of blood are diluted in 1.98 mL of diluent. This dilution is plated
on both sides of a Neubauer-ruled counting chamber. A total of 356 cells is seen when
both large center squares are counted. The platelet count expressed in SI units is
A. 178xl09/L
B. 178xl03/|xL
C. 356xl09/L
D. 712xl09/L
A. 178xl09/L
17. The size threshold range used by electrical impedance methods to count particles
as platelets is
A. 0-10 fL
B. 2-20fL
C. 15-40fL
D. 35-90fL
