Hemostasis and Coagulation Instrumentation

Question 1

1. The photo-optical method of end-point detection can be
   described as:
   a. Measurement of a color-producing chromophore at a
   wavelength of 405 nm
   b. Measurement of the change in OD of a test solution as a
   result of fibrin formation
   c. Application of an electromagnetic field to the test cuvette
   to detect the decreased motion of an iron ball within the
   cuvette
   d. Measurement of the turbidity of a test solution resulting
   from the formation of antigen-antibody complexes using latex particles

Answer 1

b. Measurement of the change in OD of a test solution as a
result of fibrin formation

Question 2

2. Modern coagulation analyzers have greatly enhanced the
   ability to perform coagulation testing as a result of which of
   the following?
   a. Maintenance of a level of accuracy and precision similar
   to that of manual methods
   b. Increase in reagent volume capabilities to improve
   sensitivity
   c. Automatic adjustment of results for interfering substances
   d. Improved flagging capabilities to identify problems in
   sample quality or instrument function

Answer 2

d. Improved flagging capabilities to identify problems in
sample quality or instrument function

Question 3

3. Which of the following is considered to be an advantage of
   the mechanical end-point detection methodology?
   a. It is not affected by lipemia in the test sample
   b. It has the ability to provide a graph of clot formation
   c. It can incorporate multiple wavelengths into a single
   testing sequence
   d. It can measure proteins that do not have fibrin formation as the end-point

Answer 3

a. It is not affected by lipemia in the test sample

Question 4

4. Which of the following methods use the principle of
   changes in light scatter or transmission to detect the endpoint of the reaction?
   a. Immunologic, mechanical, photo-optical
   b. Photo-optical, nephelometric, mechanical
   c. Photo-optical, nephelometric, immunologic
   d. Chromogenic, immunologic, mechanical

Answer 4

c. Photo-optical, nephelometric, immunologic

Question 5

5. Which of the following is a feature of semiautomated coagulation testing analyzers?
   a. The temperature is maintained externally by a heat block
   or water bath
   b. Reagents and samples usually are added manually by the
   operator
   c. Timers are automatically started as soon as the analyzer
   adds reagents to the test cuvette
   d. The end-point must be detected by the operator

Answer 5

b. Reagents and samples usually are added manually by the
operator

Question 6

6. When a sample has been flagged as being icteric by an automated coagulation analyzer, which method would be most
   susceptible to erroneous results because of the interfering
   substance?
   a. Mechanical clot detection
   b. Immunologic antigen-antibody reaction detection
   c. Photo-optical clot detection
   d. Chromogenic end-point detection

Answer 6

c. Photo-optical clot detection

Question 7

7. Platelet function testing has been incorporated into the
   routine coagulation laboratory in recent years as a result of:
   a. Increased use of drugs that stimulate platelet production
   in patients receiving chemotherapy
   b. The convenience of being able to do the testing on the
   same instrument that performs the coagulation testing
   c. Increased therapeutic use of aspirin in the treatment of
   heart disease
   d. Increased outpatient/outreach testing that prevents the
   laboratory from having access to patients to do bleeding
   time tests

Answer 7

c. Increased therapeutic use of aspirin in the treatment of
heart disease

Question 8

8. All of the following are performance characteristics to consider in the selection of a coagulation analyzer except:
   a. Location of the manufacturer’s home office
   b. Instrument footprint
   c. Ease of use for the operator
   d. Variety of tests the instrument can perform

Answer 8

a. Location of the manufacturer’s home office

Question 9

9. The PFA-100 measures platelet function by:
   a. Detecting the change in blood flow pressure along a
   small tube when a clot impairs blood flow
   b. Detecting the aggregation of latex beads coated with
   platelet activators
   c. Graphing the transmittance of light through platelet-rich
   plasma over time after addition of platelet activators
   d. Detecting the time it takes for a clot to form as blood
   flows through a small aperture in a tube coated with
   platelet activators

Answer 9

d. Detecting the time it takes for a clot to form as blood
flows through a small aperture in a tube coated with
platelet activators

Question 10

10. Point-of-care coagulation testing is used mainly:
    a. To monitor patients receiving oral anticoagulant therapy
    b. To monitor patients taking platelet inhibitors such as
    aspirin
    c. To provide a baseline for all subsequent patient test result comparisons when the patient starts any kind of
    anticoagulant therapy
    d. To monitor obstetric patients at risk of fetal loss

Answer 10

a. To monitor patients receiving oral anticoagulant therapy