Deck 39: Laboratory Testing in Coagulation

Question 1

A patient has a prolonged APTT with a normal PT.There were no errors in specimen collection.What does this mean for the patient?

A)There may be a defect in the intrinsic pathway.
B)The patient is on coumadin.
C)The patient has developed an inhibitor to a factor in the extrinsic pathway.
D)The patient has a vitamin K deficiency.

Answer 1

There may be a defect in the intrinsic pathway.

Question 2

What does the administration of recombinant factor VIIa concentrate do to the PT levels?

A)Prolongs the PT by having an absence of vitamin K
B)Shortens the PT by having an absence of factor VII
C)Shortens the PT by having increased levels of rFVIIa
D)Prolongs the PT by having thromboplastin using a recombinant TF

Answer 2

Shortens the PT by having increased levels of rFVIIa

Question 3

A citrated blood sample is tested with the following results: -PT = 60.0 seconds
-APTT = 100.0 seconds
Pending further testing, what is the most probable reason for these results?

A)The patient is in DIC.
B)The sample is clotted, and serum, not plasma, is being tested.
C)The patient is on heparin.
D)All of the above

Answer 3

All of the above

Question 4

Which of the following is needed to perform an activated partial thromboplastin time?

A)Potassium chloride and partial thromboplastin
B)Partial thromboplastin and calcium chloride
C)Thromboplastin and potassium chloride
D)Thromboplastin and calcium chloride

Question 5

What is the purpose of the INR?

A)To standardize the patient's PT worldwide
B)To minimize variability of results between laboratories
C)To minimize variability of results between lots of thromboplastin
D)All of the above

Question 6

The anticoagulant of 3.2% sodium citrate is preferred over 3.8% because:

A)It does not require an adjusted redraw on patients with high hematocrits.
B)3.8% sodium citrate tubes are no longer manufactured.
C)The 3.2% sodium citrate has more success with minimizing in vitro platelet activation.
D)It is more likely to prevent clotting with difficult draws.

Question 7

Choose the correct statement regarding proper specimen collection for coagulation testing from the choices listed below:

A)The tube needed for coagulation testing should be the first tube drawn.
B)It is acceptable to fill the sodium citrate tube halfway in a polycythemic patient for coagulation testing.
C)When drawing blood from a catheter, care must be taken to avoid heparin contamination.
D)Butterfly needles should not be used when drawing coagulation tubes.

Question 8

A patient has prolonged PT and APTT.Which of the following tests would not be warranted to follow up these findings?

A)Factor XIII assay
B)D-dimer
C)Liver function tests
D)Fibrinogen

Question 9

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

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

Question 10

A patient has severe liver disease.What test results would you expect?

A)Prolonged PT, TT, increased FDP
B)Prolonged APTT, TT
C)Decreased fibrinogen
D)Prolonged Bleeding Time, APTT

Question 11

The platelet function analyzer standardized the bleeding time method by eliminating the variables of the method.Which of the following represents the variables of bleeding time?

A)Dependence on the presence of calcium
B)Ingestion of aspirin
C)Room temperature, depth, location and direction of the incision; movement of the arm, and laboratorian experience
D)Abnormal platelet count

Question 12

A patient is admitted with prolonged epistaxis and prolonged bleeding from a recent tooth extraction.Initial screening workup reports prolonged APTT and BT, and abnormal aggregation on the PFA.Which of the following tests would help define the disorder?

A)von Willebrand's factor activity
B)von Willebrand's factor antigen
C)Factor VIII assay
D)All of the above

Question 13

The aPTT is the most common procedure used to monitor the unfractionated heparin therapy.Which of the reagents used in the testing provides the activation of the formation of the fibrin clot?

A)Thromboplastin/calcium mixture
B)Activated partial thromboplastin and calcium
C)Thrombin and fibrinogen
D)Normal pooled plasma and thrombin

Question 14

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

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

Question 15

The Prothrombin Time measures the clotting factors in the:

A)Intrinsic pathway.
B)Formation of fibrin.
C)Extrinsic pathway.
D)Fibrinolytic pathway.

Question 16

Proper pecimen collection for coagulation testing must be performed to eliminate contamination of substances that will interfere with the test results.Which of the following are considered contaminates for coagulation testing?

A)Sodium citrate and heparin anticoagulant
B)Tissue factor and anticoagulant carryover
C)Air and tissue factor
D)High hematocrit and anticoagulant carryover

Question 17

Which of the following tests is used to assess platelet function in vivo?

A)Protime
B)Activated partial thromboplastin time
C)Bleeding time
D)Platelet aggregation studies

Question 18

Why is normal pooled plasma used as the diluent in a mixing study?

A)Because it minimizes SERPIN activity
B)Because it contains 100% of all the factors needed to achieve a clot
C)Because it minimizes the effects of sodium citrate on the sample
D)Because it neutralizes any residual platelets left in the sample after centrifugation

Question 19

The Thrombin Time is prolonged with a patient having:

A)Increased levels of fibrin degration products.
B)Increased levels of fibrinogen.
C)Factor deficiencies.
D)Presence of lupus anticoagulants.

Question 20

TT = 20 sec. What is the most likely reason for these aberrant results?

A)The patient is in DIC.
B)There is heparin contamination of the sample.
C)The patient is taking coumadin.
D)The patient has liver disease.

Question 21

Using the PRP, platelet-rich plasma, in the aggregation studies of a patient's blood, the results were typical of the RIPA, ristocetin-induced platelet agglutination defect.The RIPA defect was corrected by adding normal plasma to the patient's PRP.In what disease is this seen?

A)Sticky platelet syndrome
B)Bernard-Soulier syndrome
C)Afibrinogenemia
D)von Willebrand's disease

Question 22

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

Question 23

An outpatient has an INR of 6.5.Previous testing at the same facility had results in the normal range of 2-3 for this patient on long-term anticoagulant therapy.The appropriate next step for the laboratorian would be:

A)Retest the patient sample.
B)Contact the physician ordering the test.
C)Contact the patient to return for repeat testing.
D)All of the above.

Question 24

Proper collection and processing of coagulation specimens is necessary for optimum results.What should be avoided when processing the sodium citrated specimens for testing?

A)Hemolysis and overfilling of the tube
B)Platelet-rich plasma
C)Clotting of the specimen and underfilling of the tube
D)Overfilling of the tube and lipemia

Question 25

A hemophilic patient (Hemophilia A) has a severe bleed and is being treated with Factor VIII concentrate.When testing his post-infusion, the factor VIII level does not increase.The problem could be:

A)Lupus anticoagulant.
B)Improper drawing of the specimen.
C)Factor VIII Inhibitor.
D)Factor IX inhibitor.

Question 26

What preanalytical quality control prospect is necessary when performing platelet aggregation studies?

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

Question 27

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

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

Question 28

Which of the following tests does not measure activation of the hemostatic mechanism using markers of fibrin formation and fibrinolysis?

A)Fibrinopeptide C and fibrinopeptide F
B) Thrombin-antithrombin (TAT) complex
C) Prothrombin activation fragment F1 + 2
D)Plasmin-antiplasmin (PAP) complex Correct

Question 29

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)Greater than 1-hour difference between specimen collection and analysis

Question 30

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

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

Question 31

Explain the clinical significance of a prolonged time with each of the following:

A)Bleeding time.
B)Prothrombin time.
C)Activated partial thromboplastin time.
D)Thrombin time.

Question 32

Justify the need for molecular marker testing in the workup of a hemostatic problem.

Question 33

Give the results (prolonged or normal) for the bleeding time, prothrombin time, activated partial thromboplastin time, and thrombin time for a patient on prolonged anticoagulant therapy.

Question 34

A patient with a fibrinolytic deficiency would:

A)Be prone to increased lysis.
B)Have increased levels of plasminogen.
C)Have abnormal screening tests (PT and APTT).
D)Be prone to increased clotting.

Question 35

Laboratory screening test results strongly suggest heparin contamination.Which of the following tests would help assess this finding?

A)DRVVT
B)Reptilase time
C)APTT
D)AT III activity

Question 36

In performing testing for thrombotic disorders, the ideal testing would be:

A)Antigenic measurement of PC, PS, ATIII.
B)Functional measurement of PC, PS, ATIII.
C)Platelet Function Testing.
D)Lupus anticoagulant.

Question 37

A patient's laboratory coagulation testing 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?

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

Question 38

According to the International Society on Thrombosis (ISTH), the guidelines for diagnostic criteria for LA/aPL are the demonstration of which of the following?

A)A normal phospholipid-dependent coagulation reaction.
B)Absence of a clotting factor.
C)Presence of an inhibitor.
D)Abnormal PT.

Question 39

Based on the following laboratory data: PT: normal
APTT: prolonged
Factor VIII: C assay: <1%
Which of the following is the most appropriate reflex test?

A)DRVVT
B)Bethesda titer
C)Factor IX assay
D)Mixing studies