Question 1

Which of the following tests can be used to monitor Coumadin therapy?

Accepted Answer

A)  PT-INR 
B)  Factor assays 
C)  APTT 
D)  Reptilase time

Question 2

A patient is screened positive for APCR. What does this mean?

Accepted Answer

A)  The patient is at risk for hemorrhage. 
B)  The patient has a high probability of factor VLeiden mutation. 
C)  The patient is on warfarin. 
D)  The patient is on heparin.

Question 3

Explain the effects of the following on coagulation testing:
a. Clotted sample
b. Ratio of blood to anticoagulant < 9:1
c. Patient hematocrit >55%
d. >1-hour difference between specimen collection and analysis

Accepted Answer

The answer of Explain the effects of the following on...

Question 4

Laboratory testing for von Willebrand factor contains variables that can result in difficulty in diagnosing the disease. Which of the following factors is identified as a variable that can contribute to this difficulty?

Accepted Answer

A)  Abnormal screening results 
B)  Difficulty in obtaining the specimen 
C)  Age of patient 
D)  Standardization of the reference plasma

Question 5

Normal pooled plasma is used as the diluent in a mixing study because it:

Accepted Answer

A)  Minimizes SERPIN activity 
B)  Contains 100% of all the factors needed to achieve a clot 
C)  Minimizes the effects of sodium citrate on the sample 
D)  Neutralizes any residual platelets left in the sample after centrifugation

Question 6

A patient's laboratory coagulation test results in an immediate correction of the PT and aPTT after mixing studies and no correction after performing the PT and aPTT after a 2-hour incubation at 37°C. What is the possible deficiency or inhibitor?

Accepted Answer

A)  Factor deficiency 
B)  Lupuslike anticoagulant 
C)  F-VIII inhibitor 
D)  F-V loss

Question 7

List the tests that are commonly utilized in the workup of the following:
a. von Willebrand's disease
b. Hemophilia A
c. Factor VIII inhibitor
d. Bernard-Soulier syndrome
e. TTP

Accepted Answer

The answer of List the tests that are commonly utilized...

Question 8

Which of the following instruments uses both electromechanical and optical density as a means of clot detection?

Accepted Answer

A)  STArt 4 Coagulation system 
B)  BBL Fibrosystem 
C)  Trinity Biotech Coag-A-Mate XM 
D)  AMAX Destiny Plus

Question 9

What preanalytical quality control procedures are necessary when performing platelet aggregation studies?

Accepted Answer

A)  Assess patient medications before obtaining specimen 
B)  Obtain specimen after a 12-hour fast 
C)  Perform a bleeding time before testing 
D)  Collect the specimen in a glass tube

Question 10

The international normalized ratio (INR) is used to standardize the wide variations in the reagent of prothrombin testing. What is the target goal of the ISI value in commercial reagents?

Accepted Answer

A)  Reduce the lot-to-lot variability 
B)  Correlate one manufacturer with another 
C)  Obtain a reagent that has an ISI of 1.0 or close to it 
D)  Reduce the use of anticoagulant therapy

Exam 36: Hemostasis: Laboratory Testing and Instrumentation