MCQs on Coagulation Proteins and Disorders

                      MCQ on Coagulation Proteins and Disorders

1. Which protein plays a central role in the blood clotting process by converting fibrinogen to fibrin?
a) Factor VIII
b) Factor IX
c) Factor X
d) Thrombin

2. Hemophilia A is a bleeding disorder caused by the deficiency of which coagulation factor?
a) Factor VII
b) Factor VIII
c) Factor IX
d) Factor XI

3. Vitamin K is essential for the synthesis of which group of coagulation factors?
a) Factors I, II, V, VII
b) Factors II, VII, IX, X
c) Factors V, VIII, IX, X
d) Factors XI, XII, XIII, XIV

4. Which coagulation disorder is characterized by the formation of blood clots in small blood vessels throughout the body, potentially leading to organ damage?
a) Hemophilia
b) Thrombocytopenia
c) Disseminated Intravascular Coagulation (DIC)
d) von Willebrand Disease

5. Which factor is commonly known as antihemophilic factor and is deficient in Hemophilia B?
a) Factor VIII
b) Factor IX
c) Factor XI
d) Factor XIII

6.What is the function of von Willebrand factor in the coagulation process?
a) Activates thrombin
b) Converts fibrinogen to fibrin
c) Promotes platelet adhesion and aggregation
d) Breaks down blood clots

7. Which anticoagulant protein serves as a natural anticoagulant by inhibiting factors Va and VIIIa?
a) Protein C
b) Protein S
c) Antithrombin III
d) Plasminogen

8. Which condition is characterized by an inherited deficiency of anticoagulant proteins, leading to a higher risk of venous thrombosis?
a) Hemophilia
b) Thrombocytopenia
c) Protein C deficiency
d) von Willebrand Disease

9. Which laboratory test is commonly used to monitor the extrinsic pathway of the coagulation cascade?
a) Prothrombin Time (PT)
b) Activated Partial Thromboplastin Time (APTT)
c) Thrombin Time (TT)
d) Bleeding Time (BT)

10. The hereditary deficiency of ADAMTS13 enzyme is associated with which coagulation disorder characterized by the formation of microclots in small blood vessels?
a) Hemophilia
b) Thrombocytopenia
c) Disseminated Intravascular Coagulation (DIC)
d) Thrombotic Thrombocytopenic Purpura (TTP)

11. Deficiency of which vitamin can lead to impaired coagulation due to decreased synthesis of coagulation factors?

a) Vitamin A

b) Vitamin D

c) Vitamin E

d) Vitamin K

12. What is the primary function of factor XII (Hageman factor) in the coagulation cascade?

a) Activation of thrombin

b) Activation of factor X

c) Initiation of the intrinsic pathway

d) Promotion of platelet aggregation

13. Which coagulation factor is responsible for stabilizing fibrin by cross-linking fibrin monomers?

a) Factor II (Prothrombin)

b) Factor V (Labile factor)

c) Factor VII (Proconvertin)

d) Factor XIII (Fibrin-stabilizing factor)

14. Which laboratory test is used to evaluate the intrinsic and common pathways of the coagulation cascade?

a) Activated Partial Thromboplastin Time (APTT)

b) Fibrinogen Assay

c) Prothrombin Time (PT)

d) Thrombin Time (TT)

15. Which anticoagulant is commonly used for the long-term prevention of venous thromboembolism and inhibits factor Xa directly?

a) Dabigatran

b) Enoxaparin

c) Heparin

d) Warfarin

16. What is the primary mechanism of action of heparin as an anticoagulant?

a) Inhibition of thrombin

b) Activation of antithrombin III

c) Inhibition of platelet aggregation

d) Inhibition of vitamin K synthesis

17. Which coagulation disorder is characterized by a deficiency of von Willebrand factor, leading to impaired platelet adhesion and prolonged bleeding?

a) Disseminated Intravascular Coagulation (DIC)

b) Hemophilia A 

c) Hemophilia B

d) von Willebrand disease

18. The administration of vitamin K is an effective antidote for which anticoagulant medication?

a) Direct oral anticoagulants (DOACs)

b) Warfarin

c) Heparin

d) Enoxaparin

19. Which factor deficiency is characteristic of Hemophilia C?

a) Factor VIII

b) Factor IX

c) Factor XI

d) Factor XII

20. What is the main function of tissue plasminogen activator (tPA) in the body?

a) Conversion of plasminogen to plasmin

b) Inhibition of fibrinolysis

c) Promotion of platelet aggregation

d) Stabilization of fibrin clots

Answers with Explanation:

1. d) Thrombin

Explanation: Thrombin is a key enzyme in the coagulation cascade. It converts soluble fibrinogen into insoluble fibrin, which forms the structural framework of a blood clot.

2. b) Factor VIII

Explanation: Hemophilia A, also known as classic hemophilia, is caused by a deficiency of factor VIII, an essential coagulation factor for the intrinsic pathway of clot formation.

3. b) Factors II, VII, IX, X

Explanation: Vitamin K is necessary for the synthesis of vitamin K-dependent coagulation factors, which include factors II (prothrombin), VII, IX, and X, as well as proteins C and S.

4. c) Disseminated Intravascular Coagulation (DIC)

Explanation: DIC is a condition where the normal clotting and anticoagulant mechanisms in the body are disrupted, leading to widespread clot formation and consumption of clotting factors, potentially causing organ damage.

5. b) Factor IX

Explanation: Hemophilia B, also known as Christmas disease, is caused by a deficiency of factor IX, which is also referred to as antihemophilic factor B.

6. c) Promotes platelet adhesion and aggregation

Explanation: Von Willebrand factor plays a vital role in platelet adhesion by binding platelets to the damaged vessel walls and facilitating platelet aggregation at the site of injury.

7. a) Protein C

Explanation: Protein C is an anticoagulant protein that, when activated, inhibits factors Va and VIIIa, thus downregulating the coagulation process.

8. c) Protein C deficiency

Explanation: Protein C deficiency is an inherited condition that impairs the body's ability to regulate blood clotting, increasing the risk of venous thrombosis.

9. a) Prothrombin Time (PT)

Explanation: Prothrombin Time measures the extrinsic pathway's clotting time, primarily assessing factors VII, X, V, II, and fibrinogen.

10. d) Thrombotic Thrombocytopenic Purpura (TTP)

Explanation: TTP is a disorder caused by a deficiency of ADAMTS13, an enzyme responsible for cleaving von Willebrand factor. The deficiency leads to the formation of small blood clots, resulting in thrombocytopenia and other complications.

11. d) Vitamin K

Explanation: Vitamin K is essential for the synthesis of various coagulation factors in the liver, including factors II, VII, IX, and X, as well as protein C and protein S. Its deficiency can lead to impaired blood clotting and bleeding tendencies.

12. c) Initiation of the intrinsic pathway

Explanation: Factor XII initiates the intrinsic pathway of the coagulation cascade. It triggers a series of reactions that eventually lead to the activation of factor X and the formation of a blood clot.

13. d) Factor XIII (Fibrin-stabilizing factor)

Explanation: Factor XIII is responsible for cross-linking fibrin monomers, thereby stabilizing the fibrin clot formed during coagulation.

14. a) Activated Partial Thromboplastin Time (APTT)

Explanation: APTT measures the time it takes for blood to clot through the intrinsic and common pathways. It assesses factors such as XII, XI, IX, VIII, X, V, II, and fibrinogen.

15. a) Dabigatran

Explanation: Dabigatran is a direct oral anticoagulant (DOAC) that directly inhibits thrombin (factor IIa), thereby preventing blood clot formation.

16. b) Activation of antithrombin III

Explanation: Heparin enhances the activity of antithrombin III, which in turn inhibits various coagulation factors, particularly thrombin (factor IIa) and factor Xa.

Which coagulation disorder is characterized by a deficiency of von Willebrand factor, leading to impaired platelet adhesion and prolonged bleeding?

17. d) von Willebrand disease

Explanation: Von Willebrand disease is characterized by a deficiency or dysfunction of von Willebrand factor, which plays a crucial role in platelet adhesion and stabilization of factor VIII in the circulation.

The administration of vitamin K is an effective antidote for which anticoagulant medication?

18. b) Warfarin

Explanation: Warfarin is a vitamin K antagonist. Administering vitamin K can help reverse the anticoagulant effects of warfarin by replenishing the depleted vitamin K-dependent coagulation factors.

Which factor deficiency is characteristic of Hemophilia C?

19. c) Factor XI

Explanation: Hemophilia C is caused by a deficiency of factor XI (also known as Rosenthal factor), which is involved in the intrinsic pathway of the coagulation cascade.

What is the main function of tissue plasminogen activator (tPA) in the body?

20. a) Conversion of plasminogen to plasmin

Explanation: Tissue plasminogen activator (tPA) is responsible for converting plasminogen into plasmin, an enzyme that breaks down fibrin clots and contributes to fibrinolysis, the process of clot dissolution.