(ASCP)
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 - correct answer Correct answer : A
The number of platelets an average megakaryocyte generates is approximately
A. 25-50
B. 50-200
C. 200-500
D. 2000-4000 - correct answer Correct answer : D
Which of the following is not a cause of thrombocytopenia?
A. Splenomegaly
B. Chemotherapy
C. Increased thrombopoietin
D. Aplastic anemia - correct answer Correct answer : C
Platelets interacting with and binding to other platelets is referred to as
A. Adhesion
B. Aggregation
C. Release
D. Retraction - correct answer Correct answer : B
In platelet aggregation studies, certain aggregating agents induce a biphasic aggregation curve.
This second phase 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 - correct answer Correct answer : C
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 - correct answer Correct answer : C
The platelet aggregation pattern drawn below is characteristic of the aggregating agent
See SUCCESS pg 397
A. ADP
B. Collagen
C. Ristocetin
D. Thrombin - correct answer Correct answer : B
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 - correct answer Correct answer : B
Of the following therapeutic agent, those considered to be antiplatelet medications are
A. Aspirin and Plavix
B. Coumadin and heparin
C. Heparin and protamine sulfate
D. Tissue plasminogen activator and streptokinase - correct answer Correct answer : A
,A potent inhibitor of platelet aggregation released by endothelial cells is
A. Epinephrine
B. Prostacyclin
C. Ristocetin
D. Thromboxane A2 - correct answer Correct answer : B
The reference value for mean platelet volume (MPV) is approxiamtely
A. 2-4 fL
B. 5-7 fL
C. 8-10 fL
D. 11-14 fL - correct answer Correct answer : C
The platelet parameter PDW refers to the
A. Average platelet volume
B. Call weight versus density
C. Capacity to adhere to foreign surfaces
D. Variation in platelet cell size - correct answer Correct answer : D
A normal histogram showing platelet size distribution is best described as
A. Bimodal, nonskewed peaks
B. Left-skewed single peak
C. Right-skewed single
D. Single peak, Gaussian distribution - correct answer Correct answer : C
Which of the following is not a normal maturation stage for platelets?
A. Megakaryoblast
B. Promegakaryocyte
C. Micromegakaryocyte
D. Megakaryocyte - correct answer Correct answer : C
The recommmended type of microscopy for the performance of manual platelet counts is
A. Electron
, B. Dark field
C. Light
D. Phase contrast - correct answer Correct answer : D
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. 178 x 10^9/L
B. 178 x 10^3/L
C. 356 x 10^9/L
D. 712 x 10^9/L - correct answer Correct answer : A
The size threshold range used by electircal impedance methods to count particles as plateets is
A. 0-10
B. 2-20
C. 15-40
D. 35-90 - correct answer Correct answer : B
In storage pool disease, platelets are primarily deficient in A. ADP
B. Platelet factor 3
C. Throbasthenin
D. Thromboxane A2 - correct answer Correct answer : A
The anticoagulant required for routine coagulation testing is
A. Sodium heparin
B. Sodium citrate
C. Acid citrate dextrose
D. Sodium fluoride - correct answer Correct answer : B
Which of the following is not synthesized in the liver?
A. Factor VIII
B. Plasminogen
C. Protein C