Success! In Clinical Laboratory Science – Hemostasis Practice Test

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• Electrical impedance methods count platelets in which size range?
• What is the clinical utility of thromboelastography (TEG/ROTEM)?
• What is the standard immediate reversal for warfarin in a patient requiring urgent surgery?
• Factor XII deficiency is associated with which of the following true statements?
• Which factor is primarily assessed by the PT assay?
• In platelet aggregation studies, the second phase of biphasic aggregation is directly related to?
• The size threshold range used by electrical impedance methods to count particles as platelets is
• In disseminated intravascular coagulation, what smear finding is commonly observed?
• In liver disease, which coagulation factor deficiency most contributes to prolonged PT?
• Which test is commonly used to screen for lupus anticoagulant in antiphospholipid syndrome?
• A clot retraction defect is most likely due to
• Desmopressin is used for bleeding in patients with von Willebrand disease by increasing levels of which factors?
• Which expression correctly describes a platelet count in SI units?
• Which tests best screen for von Willebrand disease?
• What is the role of antithrombin in hemostasis and how is it monitored?
• Laboratory tests requested on a patient scheduled for early morning surgery include a CBC with platelet count. An automated platelet count is 57 x 10^9/L. In the monolayer area of the peripheral blood smear, there are approximately 12 platelets per oil immersion field, many encircling neutrophils. Controls are in range. Based on this information, the best course of action is
• The platelet parameter PDW refers to the
• Which of the following is an example of a preanalytic error that can lead to falsely prolonged coagulation test results?
• A patient on unfractionated heparin therapy develops a marked drop in platelets by day 3. What is the most likely diagnosis?
• What is the expected effect of liver disease on coagulation tests?
• A patient on warfarin therapy will be deficient in a functional amount of
• Which test primarily assesses the extrinsic coagulation pathway?
• The prothrombin time will detect deficiencies in the ______ pathway(s) when calcium and a tissue factor source such as rabbit brain are added to plasma.
• Given the following laboratory results: normal platelets, slightly prolonged aPTT, normal platelet aggregation studies, and abnormal aggregation with collagen, ADP, and ristocetin, what is the appropriate reflex test?
• Platelets interacting with and binding to other platelets is referred to as?
• A 25-year-old male presents to his physician complaining of leg pain. The physician diagnoses a deep vein thrombosis (DVT) and wants to determine the cause of the thrombotic episode. Which laboratory test may be used to investigate the hypercoagulable states?
• An 85-year-old male with slurred speech and paralysis on the right side of the body is seen in the emergency department. A stat D-dimer is ordered and is very high. The physician suspects a thromboembolic event based on the D-dimer and needs to institute clot-dissolving therapy immediately. The most likely diagnosis and appropriate therapy for the patient is
• Which laboratory test would be most useful to screen for a qualitative platelet defect in a child presenting with mucocutaneous bleeding?
• A prolonged thrombin time indicates?
• INR of 1.0 would indicate that the patient is
• Which test would be least useful for monitoring apixaban activity?
• Antiphospholipid antibodies directed against phospholipid interfere with coagulation testing by binding to which molecule?
• The hemorrhagic problems associated with scurvy are due to a deficiency of what cofactor required for collagen synthesis?
• What are common causes of a prolonged PT in a patient not on anticoagulants?
• How does von Willebrand disease influence surgical bleeding risk assessment?
• What is plasmin's role in fibrinolysis and which marker indicates its activity?
• A microtainer EDTA sample obtained during a fingerstick puncture yields a platelet count of 178 x 10^9/L. In the erythrocyte monolayer of the stained peripheral blood smear, an average of nine platelets per field is seen at 1000x magnification. Based on these data, you should
• The coagulation factors referred to as 'vitamin K-dependent' are
• A patient on therapeutic warfarin will most likely have which combination of lab results?
• A 30-year-old female is admitted with neurological symptoms. Laboratory results show severe anemia, thrombocytopenia, schistocytes, and markedly decreased ADAMTS-13. What is the most likely diagnosis?
• What is the normal reference range for platelet counts in 10^9/L?
• Which statement is true regarding von Willebrand factor production?
• Thrombocytosis is a characteristic of
• When thrombin binds to thrombomodulin on the endothelial cell surface, thrombin activates which pathway?
• Thrombin time tests thrombin's action on fibrinogen.
• Of the following therapeutic agents, those considered to be antiplatelet medications are:
• Which statement about D-dimer testing is true?
• The recommended type of microscopy for the performance of manual platelet counts is
• What is the typical lab finding in mild hemophilia A?
• A 4-year-old child with petechiae and platelets 15 x 10^9/L, recent chickenpox, and a self-limited course is anticipated to recover in 2-4 weeks without treatment. What condition does this most likely represent?
• Which laboratory test is used to investigate a hypercoagulable state?
• Why are patients with von Willebrand disease prone to mucosal bleeding?
• A 6-year-old female with petechiae has prolonged PFA-100 closure time with both ADP and EPI/collagen cartridges, normal platelet aggregation except for no response to ristocetin, and MPV 16.0 fL. This pattern is most consistent with which condition?
• In this patient, which anticoagulant was used to obtain PT and aPTT results from the blood sample?
• In vitamin K deficiency, which coagulation test is typically prolonged first?
• DIC smear finding?
• Vitamin K dependent factor true statement?
• The elevated PT/INR in this patient is most consistent with therapy using which anticoagulant?
• PT/INR test assesses which coagulation pathways?
• The expected screening test result for a patient with a fibrin stabilizing factor deficiency is which?
• The ristocetin-induced platelet aggregation assay assesses which interaction?
• What are common DOACs and how are they monitored in the lab?
• Activation of the protein C pathway by thrombin–thrombomodulin serves to inactivate which factors?
• Which statement best describes the effect of thrombocytopenia on bleeding risk and routine coagulation tests?
• The anticoagulant required for routine coagulation testing is
• Bernard-Soulier syndrome is associated with which of the following?
• What is the difference between D-dimer and fibrinogen degradation products (FDP)?
• Which DOACs are Xa inhibitors and monitored by anti-Xa activity?
• Which combination is most characteristic of disseminated intravascular coagulation?
• Which statement best describes monitoring or assay selection for apixaban?
• Which of the following is the final normal maturation stage for platelets?
• Which molecule is activated by thrombin in the presence of thrombomodulin to help limit clot formation?
• In a patient with a prolonged aPTT that does not correct after a 1:1 mixing study, which diagnosis is most likely?
• Which set correctly lists the three phases of hemostasis?
• In a patient with a normal platelet count but abnormal platelet function tests, what disorders should be considered?
• Which of the following is an anticoagulant rather than an antiplatelet medication?
• Calculate the INR using the following data: Patient's PT 23.5 sec Mean normal PT 11.5 sec ISI 1.15
• The purpose of mixing studies in prolonged aPTT?
• In storage pool disease, platelets are primarily deficient in
• Phlebotomist Forgetful Frank collected a tube of blood for an aPTT in a sodium citrate tube. The tube was delivered to the laboratory at 4:30 p.m. Which statement best describes the expected results?
• What is the mechanism behind lupus anticoagulant prolonging the aPTT?
• What is the significance of abnormal fibrinogen testing?
• What pre-analytical factors can cause spurious prolongation of PT and aPTT?
• Which group of coagulation factors are vitamin K-dependent?
• If a mixing study corrects an isolated prolonged aPTT, what is the most likely cause?
• Which thrombolytic agent is used for acute ischemic stroke?
• How does disseminated intravascular coagulation affect platelet and clot quality?
• Factor VIII activity may be reduced in von Willebrand disease in which context?
• aPTT test assesses which pathways?
• Which statement about fibrinogen testing methods is true?
• How would you interpret a patient with prolonged PT and normal aPTT, normal fibrinogen, and normal platelets?
• Elevated D-dimer with prolonged PT and aPTT suggests?
• If reptilase time is normal while thrombin time is prolonged, which condition is most likely?
• Which of the following is not synthesized in the liver?
• Which of the following is a cause of thrombocytopenia?
• In monitoring a patient on oral anticoagulant therapy, an INR of 1.3 was obtained. How would you interpret this result?
• Prekallikrein deficiency is associated with which finding?
• Epsilon aminocaproic acid is the treatment of choice for
• The aPTT is a screening test for the laboratory evaluation of inherited and acquired deficiencies in which of the following?
• In von Willebrand disease, which clinical scenario is most commonly observed?
• Which statement about fibrinogen degradation products (FDP) testing is true?
• A platelet count of 180 x 10^9/L falls within the normal reference range.
• A fibrinogen assay is performed on the coagulation analyzer using the standard 1:10 dilution with Owren's buffer. The seconds obtained do not read on the standard curve. An alternate 1:20 dilution is performed and is 400 mg/dL when read off the curve. The concentration of fibrinogen to be reported in mg/dL is
• What is the most likely factor deficiency based on the following data? PT Normal, aPTT Prolonged, TT Normal
• For coagulation testing, which anticoagulant is preferred to minimize preanalytical artifacts?
• A 46-year-old man has a prolonged aPTT with a normal PT and platelets, and mixing studies return to the control value. Which condition best explains this pattern?
• D-dimer product of?
• What is a practical method to screen for factor XIII deficiency?
• Glanzmann thrombasthenia specifically involves deficiency of which platelet receptor?
• In von Willebrand disease, what perioperative management is typically required?
• DIC lab findings define DIC?
• Sex-linked recessive coagulation disorders primarily affect which gender?
• How do antiphospholipid antibodies correlate with thrombosis risk despite prolongation of coagulation assays?
• Which assay is most sensitive for detecting a direct thrombin inhibitor such as dabigatran?
• Which pair of drugs is listed as antiplatelet medications in the source material?
• Which laboratory pattern is most consistent with primary fibrinogenolysis rather than DIC in a patient with bleeding and the given results?
• What is the recommended management step when HIT is suspected?
• Which of the following enzymatically de-grades the stabilized fibrin clot?
• Why might mixing studies fail to correct an isolated prolonged aPTT?
• A 16-year-old female with frequent nosebleeds and menorrhagia has normal platelet count, prolonged aPTT, abnormal PFA-100 with ristocetin, and platelets that show no aggregation with ristocetin but normal responses to ADP, collagen, and epinephrine. This is most consistent with which disorder?
• The most likely cause of the prolonged aPTT in this patient with no bleeding history is which of the following?
• A physician suspects a qualitative platelet defect in a young child. What may be the most useful screening test listed below?
• Which coagulation pathway is primarily assessed by the aPTT?
• The platelet aggregation pattern drawn is characteristic of which aggregating agent?
• Glanzmann thrombasthenia is defined by deficiency of which platelet receptor?
• Dysfibrinogenemia is characterized by which of the following?
• How does desmopressin (DDAVP) help in von Willebrand disease?
• A potent inhibitor of platelet aggregation released by endothelial cells is?
• A newborn male with a suspected clot retraction defect has normal PFA-100, normal ristocetin aggregation, normal ADP/collagen/epinephrine aggregation, but a prolonged aPTT. These results are characteristic of which condition?
• A 3-year-old boy presents with sudden severe hemorrhagic problems. PT is normal; aPTT is markedly prolonged; mixing studies show partial correction; platelet aggregation is normal with ristocetin, ADP, collagen, and epinephrine. This pattern is most consistent with which diagnosis?
• The activity of lupus anticoagulant and anticardiolipin antibodies appears to be directed against
• D-dimer levels are negative while FDP is positive. This pattern helps distinguish primary fibrinogenolysis from DIC. Which option reflects that distinction?
• A specimen for a prothrombin time and activated partial thromboplastin time is collected in a 5 mL tube but only 2.5 mL of blood is present. What is the expected result?
• A 65-year-old patient with elevated PT/INR and suspected intracranial bleed; on oral blood thinners but the medications are not with her and she cannot communicate. Which medication would be suspected?
• A platelet aggregation agent that characteristically yields a biphasic curve in optimal concentration is?
• Which assay measures the activity of factor Xa inhibitors or heparin for monitoring therapy, especially when PT/aPTT are unreliable?
• In platelet aggregation testing, the second phase of aggregation is most closely associated with release of which substance?
• What is the pathophysiology of heparin-induced thrombocytopenia type II?
• A mixing study was performed and there was no correction of either the prolonged PT or the aPTT. What would be the likely coagulation abnormality to consider?
• How is heparin therapy monitored clinically?
• Which test is most appropriate to assess the intrinsic pathway of coagulation?
• The fibrin clot is stabilized by the activity of which enzyme?
• What would you expect in mixing studies for a patient with a factor VIII inhibitor?
• Measurement of the time required for fibrin formation when thrombin is added to plasma evaluates the
• Which test would best screen for Factor XIII deficiency?
• Which of the following will prolong the thrombin time (TT)?
• A 60-year-old male has markedly prolonged PT and aPTT when tests are performed on plasma collected in citrate, while a CBC performed on EDTA shows normal platelet counts. The best explanation is which statement?
• In mixing studies, what indicates a factor inhibitor is present?
• Which statement best describes protein C?
• In mixing studies for a prolonged aPTT, what would correction suggest?
• In a patient with atrial fibrillation and suspected DVT who is admitted on a DOAC and cannot provide the drug history, which assay would best suggest the presence of dabigatran?
• Von Willebrand factor is best described as which of the following?
• The operating principle of a photo-optic platelet aggregometer is best described as?
• Which tests are most useful to evaluate suspected antiphospholipid syndrome?
• What is the reference value for mean platelet volume (MPV)?
• A normal histogram showing platelet size distribution is best described as
• Which condition is associated with thrombocytosis?
• The coagulation factors with a sex-linked recessive inheritance pattern are which pair?
• How are liver-derived inhibitors (antithrombin, protein C/S) affected in liver disease and what is the consequence?
• For monitoring apixaban therapy, which assay is used to estimate drug concentration?
• Which parameter is used to monitor warfarin therapy, as illustrated in the patient’s case?
• Bernard-Soulier syndrome has a characteristic finding related to platelets. Which statement best describes this?
• If PT is prolonged with a normal aPTT, which factor deficiency is most likely?
• A prolonged aPTT result is obtained on a patient diagnosed with acute disseminated intravascular coagulation (DIC). The most likely cause of the prolonged aPTT is
• What is the term for a mature blood platelet?
• In a patient where dabigatran exposure is suspected, which test would be least helpful for detecting its presence?
• The main regulatory protein of secondary hemostasis is
• Which test assesses vitamin K-dependent coagulation factors?
• A 35-year-old male presents with sudden severe hemorrhagic problems. Platelet count is normal, PFA-100 is normal, PT is normal, aPTT is markedly prolonged and does not correct after a 1:1 mixing study. These findings are most consistent with which diagnosis?
• An 80-year-old man with a recent myocardial infarction has PT 52 sec, INR 5.5, and aPTT 50 sec. This pattern most likely reflects which therapy?
• Which situation would most likely cause a falsely short aPTT result?
• A suspected bleeding disorder patient shows prolonged aPTT that does not correct with 1:1 mixing with normal plasma. Which condition is most likely?
• Which laboratory test is decreased during a DIC event?
• Mixing studies correct indicates factor deficiency?
• Bernard-Soulier syndrome is characterized by which lab finding?
• Owren's buffer is used as the dilution medium in a fibrinogen assay. This implies the buffer's role is to
• PDW measures which characteristic of platelets?
• For routine coagulation testing, which anticoagulant is preferred to ensure accurate results?
• Test not affected by heparin?
• When distinguishing qualitative vs quantitative vWF defects, which tests are most informative?
• Which agents are used to treat mucosal bleeding in bleeding disorders?
• Reversal of a heparin overdose is achieved by administration of which agent?
• An advantage of the coagulation analyzers that use the electromechanical technology is that they
• How do you differentiate quantitative von Willebrand factor deficiency from qualitative defects?
• Which laboratory test is most affected by dabigatran?
• Reptilase time interpretation
• Which of the following methods depends on cleavage of synthetic substrates by an active serine protease?
• Which statement accurately describes the role of Prostacyclin in hemostasis?
• Which combination of findings would support a diagnosis of primary fibrinogenolysis?
• Which factor deficiencies prolong PT but not always aPTT?
• Which test assesses the functional activity of von Willebrand factor?
• Which finding is most characteristic of heparin-induced thrombocytopenia?
• The correct platelet count expressed in SI units is
• Which coagulation factors are vitamin K dependent?
• What is a primary laboratory manifestation of antiplatelet therapy?