Question 1

Who should select the coagulation instruments for a given laboratory?&#10;A)laboratory director&#10;B)department manager&#10;C)clinical laboratory scientists&#10;D)all of the previously listed individuals working together

Accepted Answer

Decisions regarding purchase of new equipment for the clinical laboratory should involve all those individuals listed.It also should be made in conjunction with the medical staff so that tests that are the most appropriate for the clinical situations encountered by the specific clinical laboratory are available.

Question 2

Automatic performance of certain tests based on the results of other tests is called&#10;A)reflex testing&#10;B)interpretive liberty&#10;C)programming flexibility&#10;D)random access

Accepted Answer

Reflex testing is the automatic ordering of tests based on preset parameters or the results of other tests.These reflex tests must be clearly indicated to the ordering healthcare provider at the time the initial screening test (or tests)is ordered.

Question 3

Diagnostica Stago coagulation instruments are based on what clot detection principle?&#10;A)Photo-optical&#10;B)Mechanical&#10;C)Chromogenic&#10;D)Nephelometric

Accepted Answer

Diagnostica Stago coagulation instruments use a mechanical end-point clot detection principle.These instruments magnetically monitor the movement of a steel ball within plasma.As the clot forms,the sensor detects the slowing of the ball.

Question 4

Which of the following is true regarding advances in automated coagulation instrumentation?&#10;A)Less staff training is required to operate and maintain the equipment than was necessary for earlier semiautomatic instruments.&#10;B)Single-sample testing is possible because of increased precision.&#10;C)Newer instruments are less expensive.&#10;D)Accuracy is so improved that controls do not need to be run.

Accepted Answer

Increased precision on the new automated coagulation instruments means that single-sample testing is possible.Before this,every sample had to be tested in duplicate and the duplicates had to agree within certain preset limits before they could be averaged and the result reported.

Question 5

All of the following are considered routine coagulation tests that are available in most large and small clinical laboratories except&#10;A)prothrombin time (PT).&#10;B)fibrinogen assay.&#10;C)partial thromboplastin time (PTT).&#10;D)antithrombin assay.

Accepted Answer

The antithrombin assay traditionally has not been available in most clinical laboratories,and that is still true today in small laboratories.

Question 6

What is the greatest disadvantage to photo-optical coagulation instruments?&#10;A)high cost&#10;B)complexity of operation&#10;C)availability is limited&#10;D)interference from lipemia, hemolysis, and hyperbilirubinemia

Accepted Answer

Possible interference from the presence of lipemia,hemolysis,or hyperbilirubinemia is the greatest disadvantage for photo-optical end-point detection methods.

Question 7

Using which principle does plasma become more opaque as a clot forms and the amount of light being detected decreases?&#10;A)photo-optical&#10;B)mechanical&#10;C)chromogenic&#10;D)immunologic

Accepted Answer

A light source of specified wavelength is made to pass through plasma;some light normally gets through to the detector.As a fibrin clot forms,the amount of light detected decreases.When light decreases to a predetermined deflection from the baseline,the timer stops,indicating clot formation.

Question 8

Aspirin-induced bleeding and von Willebrand disease (VWD),type 1,are detected reliably by&#10;A)platelet count.&#10;B)point-of-care testing (POCT).&#10;C)PFA 100 Platelet Function Analyzer.&#10;D)nephelometry.

Accepted Answer

The PFA 100 Platelet Function Analyzer assesses platelet dysfunction.Aspirin and VWD both negatively affect platelet function,although by entirely different mechanisms.Aspirin acetylates cyclooxygenase,thus preventing the eventual production of thromboxane A₂,an important platelet agonist.In type 1 VWD,von Willebrand factor (VWF)is decreased and therefore platelet adhesion is abnormal.The platelet count is not a reliable test for platelet function.

Question 9

Which of the following principles measures the actual coagulation protein rather than fibrin formation?&#10;A)photo-optical&#10;B)mechanical&#10;C)chromogenic&#10;D)immunologic

Accepted Answer

Immunologic methods measure the actual coagulation protein rather than fibrin formation.These assays are based on antigen-antibody reactions.

Question 10

Which of the following assays uses indirect measurement using a chromogenic substrate to quantitate heparin?&#10;A)protein C&#10;B)thrombin time (TT)&#10;C)anti-Xa assay&#10;D)fibrinogen assay

Accepted Answer

The heparin anti-Xa assay is used to indirectly measure the concentration of heparin.In this system,heparin has an inhibitory effect on the enzyme Xa.Xa normally proteolytically cleaves the chromogenic substrate,releasing the chromogen with a color intensity that is then measured.Because heparin has inhibited some of the Xa,less free Xa will be available to cleave the substrate and less color will be released.Thus the concentration of heparin is inversely proportional to the activity of Xa.This is classified as an indirect measurement.

Question 11

Examples of instrument malfunction flags include all of the following except&#10;A)temperature error.&#10;B)probe not aspirating.&#10;C)no end point detected.&#10;D)hemolysis.

Accepted Answer

The answer of Examples of instrument malfunction flags include all...

Question 12

Which of the following is the most common clot detection principle used for coagulation testing?&#10;A)photo-optical&#10;B)mechanical&#10;C)chromogenic&#10;D)immunologic

Accepted Answer

The answer of Which of the following is the most...

Question 13

Which single instrument development has been the most important improvement in coagulation instrumentation?&#10;A)multiple-sample dilutions&#10;B)improved flagging&#10;C)random access testing&#10;D)graphing of clot formation

Accepted Answer

The answer of Which single instrument development has been the...

Question 14

Which of the following most improved safety for laboratory scientists?&#10;A)closed tube sampling&#10;B)random access&#10;C)expanded computer capabilities&#10;D)improved flagging capabilities

Accepted Answer

The answer of Which of the following most improved safety...

Deck 44: Hemostasis and Coagulation Instrumentation