2.1 Coagulation and Fibrinolytic Systems/Reagents and Methods

Question 1

What of the following initiates in vito coagulation by activation of factor VII?
A. Protein C
B. Tissue factor (TF)
C. Plasmin activator
D. Thrombomodulin (TM)

Answer 1

B. Tissue factor (TF)

Question 2

Which of the following clotting factors plays a role in clotting formation in vitro, but not in vito?
A. Factor VIIa
B. Factor IIa
C. Factor XIIa
D. Factor Xa

Answer 2

C. Factor XIIa

Question 3

The anticoagulant of choice for most routine coagulation studies is:
A. Sodium oxalate
B. Sodium citrate
C. Heparin
C. Ethylenediaminetetraacetic acid (EDTA)

Answer 3

B. Sodium citrate

Question 4

Which anticoagulant: blood ratio is correct for coagulation procedures?
A. 1:4
B. 1:5
C. 1:9
D. 1:10

Answer 4

C. 1:9

Question 5

Which results would be expected for PT and APTT in a patient with polycythemia?
A. Both prolonged
B. Both shortened
C. Normal PT, prolonged APTT
D. Both normal

Answer 5

A. Both prolonged

Question 6

Which reagents are used in the PT test?
A. Thromboplastin and sodium chloride
B. Thromboplastin and potassium chloride
C. Thromboplastin and calcium
D. Actin and calcium and chloride

Answer 6

C. Thromboplastin and calcium

Question 7

Which test would be abnormal in a patient with factor X deficiency?
A. PT only
B. APTT only
C. PT and APTT
D. Thrombin time (TT)

Answer 7

C. PT and APTT

Question 8

Which clotting factors is not measured by the PT and APTT tests?
A. Factor VIII
B. Factor IX
C. Factor V
D. Factor XIII

Answer 8

D. Factor XIII

Question 9

A modification of which procedure can be used to measure fibrinogen?
A. PT
B. APTT
C. TT
D. Fibrin degradation products

Answer 9

C. TT

Question 10

Which of the following characterizes vitamin K?
A. It is required for biological activity of fibrinolysis
B. It’s activity is enhanced by heparin therapy
C. It is required for carboxylation of glutamate residues of some coagulation factors
D. It is made by endothelial cells

Answer 10

C. It is required for carboxylation of glutamate residues of some coagulation factors

Question 11

Which fragments of fibrin clot degradation are measured by the D-dimer test?
A. Fragments X and Y
B. Fibrinopeptide A and B
C. Fragments D and E
D. The D-D domains

Answer 11

D. The D-D domains

Question 12

Which of the following clotting factors are measured by the APTT test?
A. Factors II, VII, IX, X
B. Factors VII, X, II, I
C. Factors XII, XI, IX, VIII, X, V, II, I
D. Factors XII, VII, X, V, II, I

Answer 12

C. Factors XII, XI, IX, VIII, X, V, II, I

Question 13

Which coagulation test(s) would be abnormal in a patient with vitamin K deficiency?
A. PT only
B. PT and APTT
C. Fibrinogen level
D. TT

Answer 13

B. PT and APTT

Patients with vitamin K deficiency exhibit decreased production of functional prothrombin proteins (factors II, VII, IX, and X). Decreased levels of these factors prolong both PT and APTT.

Question 14

Which of the following is correct regarding the international normalized ration (INR)?
A. It uses the international sensitivity ratio (ISR)
B. It standardizes PT results
C. It standardizes APTT results
D. It is used to monitor heparin therapy

Answer 14

B. PT and APTT

Question 15

Which of the following is referred to as an endogenous activator of plasminogen?
A. Streptokinase
B. Transamidase
C. Tissue plasminogen activator (tPA)
D. tPA inhibitor

Answer 15

C. Tissue plasminogen activator (tPA)

Question 16

Which protein is the primary inhibitor of the fibrinolytic system?
A. Protein C
B. Protein S
C. alpha2-Antiplasmin
D. alpha2-Macroglobulin

Answer 16

C. alpha2-Antiplasmin

Question 17

Which of the following statements is correct regarding the D-dimer test?
A. Levels are decreased in DIC
B. Test detects polypeptides A and B
C. Test detects fragments D and E
D. Test has a negative predictive value

Answer 17

D. Test has a negative predictive value

Question 18

A protein that plays a role in both coagulation and PLT aggregation is:
A. Factor I
B. Factor VIII
C. Factor IX
D. Factor XI

Answer 18

A. Factor I

Question 19

A standard 4.5-mL blue-top tube filled with 3.0 mL of blood was submitted to the laboratory for PT and APTT tests. The sample is from a patient undergoing surgery the following morning for a tonsillectomy. Which of the following is the necessary course of action by the medical laboratory scientist?
A. Run both tests in duplicate and report the average result
B. Reject the sample and request a new sample
C. Report the PT results
D. Report the APTT result

Answer 19

B. Reject the sample and request a new sample

Question 20

Which statement is correct regarding sample storage for the PT test?
A. Stable for 24 hours if the sample is capped
B. Stable for 24 hours if the sample is refrigerated at 4C
C. Stable for 4 hours if the sample is stored at 4C
D. Should be run within 8 hours

Answer 20

A. Stable for 24 hours if the sample is capped

Question 21

In primary fibrinolysis, the fibrinolytic activity results in response to:
A. Increased fibrin formation
B. Spontaneous activation of fibrinolysis
C. Increased fibrin monomers
D. DIC

Answer 21

B. Spontaneous activation of fibrinolysis

Question 22

Plasminogen deficiency is associated with:
A. Bleeding
B. Thrombosis
C. Increased fibrinolysis
D. Increased coagulation

Answer 22

B. Thrombosis

Question 23

Which of the following clotting factors are activated by thrombin that is generated by tissue pathways (TF-VIIa)?
A. Factors XII, XI
B. Factors XII, I
C. Factors I, II
D. Factors V, VIII

Answer 23

D. Factors V, VIII

Question 24

Which substrate is used in a chromogenic factor assay?
A. p-nitroaniline (pNa)
B. Chloroprenol red
C. Prussian blue
D. Ferricyanide

Answer 24

A. p-nitroaniline (pNa)

Question 25

Which of the following antibodies is used in the D-dimer assay?
A. Polyclonal antibody directed against X and Y fragments
B. Polyclonal antibody directed against D-dimer
C. Monoclonal antibody against D and E fragments
D. Monoclonal antibody against D-dimer

Answer 25

D. Monoclonal antibody against D-dimer