Haemostasis MCQs: Master Coagulation & Bleeding Control – 30 MCQs | Kenya MBChB

30 Year 3: Blood Transfusion exam questions on Haemostasis MCQs: Master Coagulation & Bleeding Control for medical students. Includes MCQs, answers, explanation

This MCQ set contains 30 questions on Haemostasis MCQs: Master Coagulation & Bleeding Control in the Year 3: Blood Transfusion unit. Each question includes the correct answer and a detailed explanation for active recall and exam preparation.

Q1: What is haemostasis?

  1. A. Production of new blood cells
  2. B. Process by which bleeding stops
  3. C. Normal body condition
  4. D. None of the above

Correct answer: B – Process by which bleeding stops

Haemostasis is the physiological sequence that arrests bleeding through vasoconstriction, platelet plug, and coagulation.

Q2: Which vitamin is essential for synthesis of coagulation factors?

  1. A. Vitamin C
  2. B. Vitamin B
  3. C. Vitamin D
  4. D. Vitamin K

Correct answer: D – Vitamin K

Vitamin K is required for gamma-carboxylation of factors II, VII, IX, and X — making them functional.

Q3: Fibrinogen is also known as?

  1. A. Factor XIII
  2. B. Factor I
  3. C. Factor II
  4. D. Factor III

Correct answer: B – Factor I

Fibrinogen = Factor I; thrombin cleaves it to form fibrin, the structural component of a clot.

Q4: Which is NOT one of the four major physiologic events of haemostasis?

  1. A. Fibrinolysis
  2. B. Platelet plug formation
  3. C. Vasoconstriction
  4. D. Coagulation

Correct answer: A – Fibrinolysis

The four events are: vascular spasm, platelet plug, coagulation, and clot retraction/repair. Fibrinolysis is clot dissolution — a separate process.

Q5: First step in haemostasis when a blood vessel is injured?

  1. A. Platelet plug formation
  2. B. Vascular spasm
  3. C. Coagulation
  4. D. Fibrinolysis

Correct answer: B – Vascular spasm

The immediate response to vascular injury is smooth muscle contraction (vasoconstriction) to reduce blood flow.

Q6: Which mineral is essential for the clotting process?

  1. A. Sodium
  2. B. Phospholipid
  3. C. Iron
  4. D. Calcium

Correct answer: D – Calcium

Calcium (Factor IV) is required as a cofactor at multiple steps in the coagulation cascade.

Q7: Deficiency of Factor VIII leads to?

  1. A. Hemolysis
  2. B. Hemophilia A
  3. C. Hemophilia B
  4. D. Thrombocytopenia

Correct answer: B – Hemophilia A

Factor VIII deficiency = Hemophilia A; Factor IX deficiency = Hemophilia B (Christmas disease).

Q8: Which factor is known as the "Christmas factor"?

  1. A. Factor IX
  2. B. Factor VIII
  3. C. Factor X
  4. D. Factor VII

Correct answer: A – Factor IX

Named after Stephen Christmas, the first patient diagnosed with Factor IX deficiency (Hemophilia B).

Q9: Which of the following is a natural anticoagulant?

  1. A. Factor VII
  2. B. Heparin
  3. C. Factor IX
  4. D. Fibrinogen

Correct answer: B – Heparin

Heparin (endogenous, from mast cells) potentiates antithrombin III to inhibit thrombin and Factor Xa.

Q10: Main function of von Willebrand factor?

  1. A. Activates fibrinogen
  2. B. Inhibits thrombin
  3. C. Binds platelets to collagen
  4. D. Cross-links fibrin

Correct answer: C – Binds platelets to collagen

vWF acts as a bridge between exposed subendothelial collagen and platelet GPIb receptors, initiating primary haemostasis.

Q11: Which test screens for platelet and blood vessel function?

  1. A. RBC count
  2. B. CBC
  3. C. APTT
  4. D. Bleeding time

Correct answer: D – Bleeding time

Bleeding time assesses primary haemostasis (platelet plug formation and vascular response), not the coagulation cascade.

Q12: Which pathway does warfarin primarily affect?

  1. A. Intrinsic
  2. B. Extrinsic
  3. C. Common
  4. D. Fibrinolytic

Correct answer: B – Extrinsic

Warfarin most noticeably affects Factor VII (shortest half-life), exclusive to the extrinsic pathway — hence PT/INR monitors it.

Q13: End product of the coagulation cascade?

  1. A. Platelet plug
  2. B. Soluble fibrinogen
  3. C. Insoluble fibrin clot
  4. D. Plasmin

Correct answer: C – Insoluble fibrin clot

Thrombin cleaves fibrinogen → fibrin monomers → polymerize → cross-linked by Factor XIIIa into a stable insoluble clot.

Q14: Which factor stabilizes the fibrin clot by cross-linking fibrin?

  1. A. Factor Xa
  2. B. Factor XIIIa
  3. C. Factor IIa
  4. D. Factor VIIIa

Correct answer: B – Factor XIIIa

Thrombin activates Factor XIII → Factor XIIIa cross-links fibrin strands, making the clot resistant to fibrinolysis.

Q15: Which is responsible for fibrinolysis?

  1. A. Tissue plasminogen activator (tPA)
  2. B. Factor XIII
  3. C. Tissue factor
  4. D. Phospholipid

Correct answer: A – Tissue plasminogen activator (tPA)

tPA converts plasminogen → plasmin, which digests fibrin and dissolves clots.

Q16: Which color vial is used for coagulation studies?

  1. A. Red
  2. B. Purple
  3. C. Light blue
  4. D. Green

Correct answer: C – Light blue

Light blue (sodium citrate) tubes are used for PT, aPTT, and other coagulation tests.

Q17: Main cause of increased PT?

  1. A. Increased Factor VII
  2. B. Increased Factor VIII
  3. C. Decreased Factor I
  4. D. Decreased Factor VII

Correct answer: D – Decreased Factor VII

PT measures the extrinsic pathway; Factor VII deficiency or warfarin (which most affects Factor VII) prolongs PT.

Q18: Which is NOT released by activated platelets?

  1. A. Serotonin
  2. B. ADP
  3. C. Urea
  4. D. Ca²⁺ ions

Correct answer: C – Urea

Activated platelets release ADP, serotonin, thromboxane A2, and calcium. Urea is a waste product, not released by platelets.

Q19: Function of antithrombin III?

  1. A. Activates platelets
  2. B. Inhibits thrombin
  3. C. Cross-links fibrin
  4. D. Activates Factor VII

Correct answer: B – Inhibits thrombin

ATIII is the main physiological inhibitor of thrombin and Factor Xa; heparin greatly enhances its activity.

Q20: Which test monitors heparin therapy?

  1. A. PT
  2. B. Bleeding time
  3. C. APTT
  4. D. Thrombin time

Correct answer: C – APTT

Heparin acts on the intrinsic pathway via ATIII; aPTT monitors this with a therapeutic target of 1.5–2.5× control.

Q21: Main abnormality in von Willebrand disease?

  1. A. Platelet deficiency
  2. B. Lack of von Willebrand factor
  3. C. Factor X deficiency
  4. D. Excess fibrinogen

Correct answer: B – Lack of von Willebrand factor

vWD is the most common inherited bleeding disorder, caused by absent or dysfunctional vWF protein.

Q22: Which is NOT a step in haemostasis?

  1. A. Vascular spasm
  2. B. Platelet plug formation
  3. C. Leukocyte migration
  4. D. Coagulation

Correct answer: C – Leukocyte migration

Leukocyte migration is part of the inflammatory response, not a component of haemostasis.

Q23: Which factor converts prothrombin to thrombin?

  1. A. Factor VII
  2. B. Factor Xa
  3. C. Factor XIII
  4. D. Factor IX

Correct answer: B – Factor Xa

Factor Xa, together with Factor Va (prothrombinase complex) on a phospholipid surface, cleaves prothrombin to thrombin.

Q24: Screening test for the extrinsic pathway?

  1. A. APTT
  2. B. Bleeding time
  3. C. PT
  4. D. Thrombin time

Correct answer: C – PT

PT measures the extrinsic (Factor VII + tissue factor) and common pathways.

Q25: Disorder characterized by low platelet count?

  1. A. Hemophilia
  2. B. Thrombocytopenia
  3. C. Polycythemia
  4. D. Leukemia

Correct answer: B – Thrombocytopenia

Thrombocytopenia = platelet count <150,000/μL; causes include ITP, bone marrow failure, and HIT.

View on OmpathStudy