2.1 Coagulation and Fibrinolytic Systems/Reagents and Methods

Question 1

Which of the following initiates in vivo coagulation by activation of factor VII?

Answer 1

Tissue factor (TF)

Question 2

Which of the following clotting factors plays a role in clot formation in vitro, but not in vivo?

Answer 2

Factor XIIa

Question 3

The anticoagulant of choice for most routine coagulation studies is:

Answer 3

Sodium citrate

Question 4

Which anticoagulant:blood ratio is correct for coagulation procedures?

Answer 4

1:9

Question 5

Which results would be expected for PT and APTT in a patient with polycythemia?

Answer 5

Both prolonged

Question 6

Which reagents are used in the PT test?

Answer 6

Thromboplastin and calcium

Question 7

Which test would be abnormal in a patient with factor X deficiency?

Answer 7

PT and APTT

Question 8

Which clotting factor is not measured by the PT and APTT tests?

Answer 8

Factor XIII

Question 9

A modification of which procedure can be used to measure fibrinogen?

Answer 9

TT

Question 10

Which of the following characterizes vitamin K?

Answer 10

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?

Answer 11

The D-D domains

Question 12

Which of the following clotting factors are measured by the APTT test?

Answer 12

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?

Answer 13

PT and APTT

Question 14

Which of the following is correct regarding the international normalized ratio (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

It standardizes PT results

Question 15

Which of the following is referred to as an endogenous activator of plasminogen?

Answer 15

Tissue plasminogen activator (tPA)

Question 16

Which protein is the primary inhibitor of the fibrinolytic system?

Answer 16

α2-Antiplasmin

Question 17

Which of the following statements is correct regarding the D-dimer test?

Answer 17

Test has a negative predictive value

Question 18

A protein that plays a role in both coagulation and PLT aggregation is:

Answer 18

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?

Answer 19

Reject the sample and request a new sample

Question 20

Which statement is correct regarding sample storage for the PT test?

Answer 20

Stable for 24 hours if the sample is capped

Question 21

In primary fibrinolysis, the fibrinolytic activity results in response to:

Answer 21

Spontaneous activation of fibrinolysis

Question 22

Plasminogen deficiency is associated with:

Answer 22

Thrombosis

Question 23

Which of the following clotting factors are activated by thrombin that is generated by tissue pathway (TF-VIIa)?

Answer 23

Factors V, VIII

Question 24

Which substrate is used in a chromogenic factor assay?

Answer 24

p-nitroaniline (pNa)

Question 25

Which of the following antibodies is used in the D-dimer assay?

Answer 25

Monoclonal antibody against D-dimer