Chapter 44

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

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

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

a. Location of the manufacturer's home office

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

a. To monitor patients receiving oral anticoagulant therapy

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

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

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

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

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

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

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

c. Photo-optical clot detection

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

c. Photo-optical, nephelometric, immunologic

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

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

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

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