Welcome to Part 41 of our Free ASCP MLS Exam Practice Questions series. This section covers Hemostasis and Coagulation Disorders, which are critical topics in both clinical practice and the ASCP MLS exam. These disorders highlight the delicate balance of clot formation and dissolution that prevents both bleeding and thrombosis.
🔹 Topics Covered in This Part
- Laboratory evaluation: PT, aPTT, INR, mixing studies, factor assays
- Physiology of hemostasis: primary and secondary pathways
- Coagulation cascade: intrinsic, extrinsic, and common pathways
- Hemophilia A and B, and other factor deficiencies
- Von Willebrand disease (types, diagnosis, management)
- Disseminated intravascular coagulation (DIC)
60 MCQs (3401- 3460):
📘 How to Use These Practice Questions
- The questions in this section test your knowledge of pathophysiology, clinical presentation, and lab testing for coagulation disorders.
- Numbering continues from the previous article — starting at Question 3401.
- Answer keys with explanations will follow at the end to enhance exam preparation.
- What is the average life span of a platelet in peripheral blood?
a) 5 days
b) 10 days
c) 20 days
d) 30 days - Aspirin impairs platelet function by which primary mechanism?
a) Depleting platelet alpha granule content
b) Inactivating ADP and phospholipase A2
c) Inactivating cyclooxygenase, which blocks thromboxane A2 production
d) Impairing von Willebrand factor - In patients with bleeding disorders caused by platelets, the most common type of bleeding is:
a) Hemarthrosis
b) Delayed bleeding
c) Deep hematomas
d) Mucosal bleeding - Which of the following is a direct antiplatelet agent?
a) Argatroban
b) Hirudin
c) Dabigatran
d) Tirofiban - The drugs ticlopidine and clopidogrel inhibit platelets by interfering with:
a) von Willebrand factor binding
b) ADP-mediated platelet aggregation
c) The GPIIb/IIIa receptor
d) Cyclooxygenase enzyme - Von Willebrand factor mediates platelet adhesion by binding to which platelet receptor?
a) GPIIb/IIIa
b) GPIb/IX/V
c) GPIa/IIa
d) GPIV - Which of the following conditions presents as a quantitative platelet disorder?
a) Von Willebrand disease
b) Hemophilia A
c) Glanzmann thrombasthenia
d) May-Hegglin anomaly - Which statement is true of acute Idiopathic Thrombocytopenic Purpura (ITP)?
a) It is found primarily in adults
b) Spontaneous remission usually occurs within several weeks
c) Women are more commonly affected
d) Peripheral destruction of platelets is decreased - The most common cause of bleeding in patients is:
a) A qualitative platelet defect
b) A qualitative abnormality of fibrinogen
c) A quantitative abnormality of fibrinogen
d) A quantitative abnormality of platelets (thrombocytopenia) - A post-operative patient has oozing from a surgical wound. Lab results show normal PT/aPTT and fibrinogen, but a platelet count of 40 x 10³/µL. The most likely cause is:
a) Dilution of coagulation factors
b) Intravascular coagulation
c) Hypofibrinogenemia
d) Dilutional thrombocytopenia - A deficiency of the ADAMTS13 enzyme is responsible for thrombocytopenia in:
a) Thrombotic Thrombocytopenic Purpura (TTP)
b) Disseminated Intravascular Coagulation (DIC)
c) Hemolytic Uremic Syndrome (HUS)
d) Idiopathic Thrombocytopenic Purpura (ITP) - In Heparin-Induced Thrombocytopenia (HIT), antibodies are produced against which complex?
a) Anticardiolipin (ACLA)
b) Platelet Factor 4 (PF4)
c) Antithrombin (AT)
d) Beta-2-glycoprotein 1 (B2GP1) - In Polycythemia Vera, the platelet count is typically:
a) Elevated
b) Normal
c) Decreased
d) Variable - A patient presents with a platelet count of 900 x 10³/µL and giant, bizarre-shaped platelets. This is most compatible with:
a) Reactive thrombocytosis
b) Myelofibrosis
c) Idiopathic thrombocythemia (Essential thrombocythemia)
d) Congenital spherocytosis - Large blue cytoplasmic inclusions in white blood cells are a characteristic finding in:
a) Wiskott-Aldrich syndrome
b) May-Hegglin Anomaly
c) Ehlers-Danlos syndrome
d) Hermansky-Pudlak syndrome - Von Willebrand factor is synthesized in which cell type?
a) Hepatocytes
b) Endothelial cells
c) Megakaryocytes
d) Monocytes - A normal platelet count with abnormal platelet function is characteristic of:
a) Idiopathic Thrombocytopenic Purpura (ITP)
b) Thrombotic Thrombocytopenic Purpura (TTP)
c) Glanzmann thrombasthenia
d) May-Hegglin anomaly - Which of the following is a characteristic finding in Bernard-Soulier syndrome?
a) Defective GPIIb/IIIa receptor
b) Absent GPIb/IX/V receptor
c) Deficiency of ADP receptors
d) Lack of dense granules - The bleeding time test is most affected by which of the following?
a) Factor VIII deficiency
b) Vitamin K deficiency
c) Severe von Willebrand disease
d) Mild factor XI deficiency - A patient with thrombocytopenia, microangiopathic hemolytic anemia, and neurological symptoms most likely has:
a) Idiopathic Thrombocytopenic Purpura (ITP)
b) Hemolytic Uremic Syndrome (HUS)
c) Thrombotic Thrombocytopenic Purpura (TTP)
d) Heparin-Induced Thrombocytopenia (HIT) - Thrombocytopenia and albinism are associated with:
a) Wiskott-Aldrich syndrome
b) May-Hegglin Anomaly
c) Hermansky-Pudlak syndrome
d) Chédiak-Higashi syndrome - The antiplatelet drug abciximab works by which mechanism?
a) ADP receptor antagonism
b) GPIIb/IIIa receptor blockade
c) Cyclooxygenase inhibition
d) Phosphodiesterase inhibition - In a patient with uremia, the bleeding tendency is primarily due to:
a) Thrombocytopenia
b) A qualitative platelet defect
c) Factor VIII deficiency
d) Hyperfibrinolysis - Which of the following is characterized by thrombocytopenia, eczema, and immunodeficiency?
a) Wiskott-Aldrich syndrome
b) May-Hegglin Anomaly
c) Hermansky-Pudlak syndrome
d) Scott syndrome - A patient on warfarin therapy would be expected to have a prolonged:
a) Bleeding time
b) Thrombin time
c) Prothrombin time (PT)
d) Activated clotting time (ACT) - The prothrombin time (PT) test is most sensitive to deficiencies in which pathway?
a) Intrinsic pathway
b) Extrinsic pathway
c) Common pathway
d) Fibrinolytic pathway - Hemophilia A is caused by a deficiency of which coagulation factor?
a) Factor VIII
b) Factor IX
c) Factor XI
d) Factor XII - The activated partial thromboplastin time (aPTT) test is most sensitive to deficiencies in which pathway?
a) Intrinsic pathway
b) Extrinsic pathway
c) Common pathway
d) Fibrinolytic pathway - Which of the following is a vitamin K-dependent coagulation factor?
a) Factor V
b) Factor VIII
c) Factor XI
d) Factor II (Prothrombin) - The thrombin time (TT) measures the final step of coagulation, which is:
a) The activation of factor X
b) The conversion of prothrombin to thrombin
c) The conversion of fibrinogen to fibrin
d) The cross-linking of fibrin - 490. Which factor deficiency causes Hemophilia A?
a) Factor IX
b) Factor VIII
c) Factor XI
d) Factor VII - Hemophilia B is caused by deficiency of:
a) Factor VIII
b) Factor IX
c) Factor XI
d) Factor XIII - Which laboratory test is typically prolonged in hemophilia A and B?
a) PT
b) aPTT
c) Thrombin time
d) Bleeding time - Von Willebrand disease is due to:
a) Platelet receptor deficiency
b) Decreased or defective vWF
c) Factor V deficiency
d) Decreased fibrinogen - Which test is abnormal in both platelet disorders and vWD?
a) PT
b) aPTT
c) Bleeding time
d) D-dimer - Which factor stabilizes fibrin clots?
a) Factor VII
b) Factor XIII
c) Factor IX
d) Factor V - The most common inherited bleeding disorder is:
a) Hemophilia A
b) Hemophilia B
c) Von Willebrand disease
d) Factor XI deficiency - Which condition shows prolonged PT and aPTT with low fibrinogen?
a) Hemophilia A
b) Hemophilia B
c) DIC
d) vWD - D-dimer is a marker for:
a) Fibrinolysis
b) Platelet count
c) Fibrinogen activity
d) Factor XIII deficiency - Which of the following is a vitamin K–dependent factor?
a) Factor VIII
b) Factor IX
c) Factor XI
d) Factor XII - Which anticoagulant works by inhibiting vitamin K?
a) Heparin
b) Warfarin
c) Direct thrombin inhibitors
d) Aspirin - The antidote for heparin overdose is:
a) Vitamin K
b) Protamine sulfate
c) Fresh frozen plasma
d) Platelet transfusion - Which condition is associated with factor V Leiden mutation?
a) Hemophilia A
b) Increased risk of thrombosis
c) vWD
d) DIC - Which laboratory finding is characteristic of liver disease–related coagulopathy?
a) Normal PT and PTT
b) Prolonged PT and PTT with decreased clotting factors
c) Normal fibrinogen
d) Isolated factor VIII deficiency - Which test evaluates the extrinsic pathway of coagulation?
a) aPTT
b) PT
c) Thrombin time
d) Bleeding time - Which pathway does the aPTT primarily evaluate?
a) Extrinsic
b) Intrinsic
c) Platelet
d) Fibrinolysis - Which factor deficiency leads to prolonged PT but normal aPTT?
a) Factor VII
b) Factor VIII
c) Factor IX
d) Factor XI - Which factor deficiency leads to prolonged aPTT but normal PT?
a) Factor VII
b) Factor VIII
c) Factor X
d) Factor V - Which factor is not produced in the liver?
a) Factor VIII
b) Factor IX
c) Factor VII
d) Factor X - Which test measures the conversion of fibrinogen to fibrin?
a) PT
b) aPTT
c) Thrombin time
d) D-dimer - Which deficiency is associated with prolonged bleeding after surgery but not spontaneous bleeding?
a) Factor XII deficiency
b) Factor VIII deficiency
c) Factor IX deficiency
d) vWF deficiency - Which anticoagulant enhances antithrombin activity?
a) Warfarin
b) Heparin
c) Aspirin
d) Streptokinase - Mixing studies are used to differentiate:
a) Platelet vs coagulation factor disorders
b) Factor deficiency vs inhibitor presence
c) Extrinsic vs intrinsic pathway
d) Primary vs secondary hemostasis - Which condition is associated with lupus anticoagulant?
a) Prolonged PT and bleeding tendency
b) Prolonged aPTT but thrombosis risk
c) Normal coagulation tests
d) Isolated thrombocytopenia - Which of the following is a natural anticoagulant protein?
a) Factor VIII
b) Protein C
c) Factor IX
d) Fibrinogen - Which disorder is associated with low platelets, prolonged PT and aPTT, and high D-dimer?
a) ITP
b) TTP
c) DIC
d) Hemophilia A - Which test is commonly used to monitor warfarin therapy?
a) aPTT
b) PT/INR
c) Thrombin time
d) Platelet count - Which test is commonly used to monitor unfractionated heparin therapy?
a) PT
b) aPTT
c) D-dimer
d) Bleeding time - Which factor is deficient in Hemophilia C?
a) Factor XI
b) Factor IX
c) Factor VIII
d) Factor XIII - A patient with mucocutaneous bleeding, prolonged bleeding time, and low ristocetin-induced platelet aggregation most likely has:
a) Hemophilia A
b) vWD
c) Factor VII deficiency
d) Factor XIII deficiency
📌 How to Use This Practice Set
- Answer each question before checking the key.
- Focus on why the correct answer is right and the others are wrong.
- Use this set as timed practice to simulate the real exam environment.
Answer Key
Answer Key:
- b) 10 days
- c) Inactivating cyclooxygenase, which blocks thromboxane A2 production
- d) Mucosal bleeding
- d) Tirofiban
- b) ADP-mediated platelet aggregation
- b) GPIb/IX/V
- d) May-Hegglin anomaly
- b) Spontaneous remission usually occurs within several weeks
- d) A quantitative abnormality of platelets (thrombocytopenia)
- d) Dilutional thrombocytopenia
- a) Thrombotic Thrombocytopenic Purpura (TTP)
- b) Platelet Factor 4 (PF4)
- a) Elevated
- c) Idiopathic thrombocythemia (Essential thrombocythemia)
- b) May-Hegglin Anomaly
- b) Endothelial cells
- c) Glanzmann thrombasthenia
- b) Absent GPIb/IX/V receptor
- c) Severe von Willebrand disease
- c) Thrombotic Thrombocytopenic Purpura (TTP)
- c) Hermansky-Pudlak syndrome
- b) GPIIb/IIIa receptor blockade
- b) A qualitative platelet defect
- a) Wiskott-Aldrich syndrome
- c) Prothrombin time (PT)
- b) Extrinsic pathway
- a) Factor VIII
- a) Intrinsic pathway
- d) Factor II (Prothrombin)
- c) The conversion of fibrinogen to fibrin
- b) Factor VIII
- b) Factor IX
- b) aPTT
- b) Decreased or defective vWF
- c) Bleeding time
- b) Factor XIII
- c) Von Willebrand disease
- c) DIC
- a) Fibrinolysis
- b) Factor IX
- b) Warfarin
- b) Protamine sulfate
- b) Increased risk of thrombosis
- b) Prolonged PT and PTT with decreased clotting factors
- b) PT
- b) Intrinsic
- a) Factor VII
- b) Factor VIII
- a) Factor VIII
- c) Thrombin time
- a) Factor XII deficiency
- b) Heparin
- b) Factor deficiency vs inhibitor presence
- b) Prolonged aPTT but thrombosis risk
- b) Protein C
- c) DIC
- b) PT/INR
- b) aPTT
- a) Factor XI
- b) vWD
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