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2012-08-28 20:53:46
Lab Tech ll

Lab Tech ll
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  1. List the parts of the normal hemostatic mechanism.
    • primary hemostasis:  vessel wall & thrombocytes
    • secondary hemostasis:  coagulation factors form fibrin
    • fibrinolysis:  plamin dissolves fibrin
  2. List 5 different mechanisms by which hemostatic disorders can be produced.
    • thrombocytopenia
    • thrombocytopathy
    • hemophilia A & B
    • von Willebrand's disease
    • coumarin toxicity
    • DIC
  3. List 6 different clinical signs associated with hemostatic disorders.
    • petechiae & ecchymosis
    • epistaxis
    • hematuria
    • melenia
    • ocular hemorrhage
    • gingival bleeding
    • bruises
    • hematomas
    • bleeding into sub q, muscles, and joints
  4. Which anticoagulant is used for coagulation factor tests?
    sodium citrate
  5. Define megakaryocyte.
    cell in bone marrow that thrombocytes break off of
  6. Define activated clotting time.
    tests intrinsic/common pathways (secondary hemstasis)
  7. Define petechia
    little hemorrhages
  8. Define epistaxis.
    nose bleed
  9. Define coumarin.
  10. Define DIC
    clots occuring intravascularly all over the body.
  11. Define melena.
    digestive blood in poop
  12. Name 3 inherited hemostatic disorders.
    • Hemophilia
    • vonWillebrand's disease
  13. Name 4 diseases often associated with hemostatic disorders.
    • DIC
    • vonWillebrand's disease
    • hemophilia
    • coumarin toxicity
  14. List three pathophysiologic mechanisms by with a thrombocytopenia may be produced.
    • decreased production
    • increased destruction
    • consumption
    • sequestration
  15. List three different tests which may be run on the SCA 2000.
    • ACT
    • OSPT
    • APTT
  16. What is hemostasis?
    • coagulation
    • blood clotting
    • a protective mechanism
    • prevents blood loss due to minor injury
    • protects against disorders that cause bleeding
  17. What is thrombocytopathy?
    disease of thrombocytes not functioning correctly
  18. What is thrombocytopenia?
    decrease in the normal amount of thrombocytes
  19. What does DIC stand for?
    dissemenated intravascular coagulation
  20. What happens when there is injury to the vessel wall?
    vasoconstriction occurs within seconds which stimulates the release of factor III
  21. How long does vasoconstriction last when there is injury to the vessel wall?
    lasts less than 1 minute
  22. Are vasculopathies rare?
  23. Where are thrombocytes produced?
    in bone marrow
  24. What do thrombocytes adhere to?
    subendothelial collagen of vessel walls
  25. What do thrombocytes release?
    bioactive substances
  26. What do thrombocytes stimulate?
    second degree of hemostasis
  27. Where are clotting factor produced?
    in the liver
  28. Which clotting factor is not produced in the liver?
  29. How many clotting factors are there?
  30. What do clotting factors function as?
    enzymes activating on another
  31. Do we need all 12 clotting factors to get fibrin?
  32. What happens if we do not have all 12 clotting factors?
    unstable clot that will cause bleeding again
  33. What are the three different chemical reactions in clotting factors?
    • intrinsic pathway
    • extrinsic pathway
    • common pathway
  34. What is the end result of the clotting factors pathway?
  35. What does fibrin do?
    stabilizes platelet plug
  36. What does anticoagulants do?  What does EDTA specifically act on?  Heparin?
    • act on clotting factors to prevent clotting
    • EDTA removes calcium from the blood
    • Heparin prevents prothrombin from converting to thrombine
  37. What are the clotting factors in the extrinsic pathway?
    • factor III
    • factor VII
    • Ca
  38. What are the clotting factors in the intrinsic pathway?
    factors XII, XI, IX, VIII, VI, Ca
  39. What are the clotting factors in the common pathway?
    Factors X, V, IV, III, II, I
  40. Which clotting factor is the most important in the extrinsic pathway?  What is it specifically?
    • factor VII
    • vitamin K
  41. What is factor I?
  42. Where are the intrinsic pathways?
    • all within the vessel
    • already found in blood
  43. How is the extrinsic pathway activated?
    tissue factor III activated by tissue injury
  44. What is needed to make factor VII?
    vitamin K
  45. What is the common pathway?
    where intrinsic and extrinsic pathways come together
  46. In the common pathway, X, V, and calcium activate what?  What does the reaction do?
    • X, V, and calcium activate factor II
    • prothrombin turns to thrombin
  47. Factor II activate what?  What does this reaction do?
    • factor II activates factor I
    • fibrinogen turns to fibrin
  48. What are the signs and defects of secondary hemostasis?
    • bruises and hematomas
    • bleeding into sub q, muscles, and joints
  49. When does fibrinolysis occur?
    after the clot has formed
  50. In fibrinolysis, plasminogen is converted to what?
  51. Plasmin are fragments of what?
  52. Where is fibrin removed?
    by the liver
  53. Is a detailed history from the owner important when diagnosing hemostatic disorders?
  54. What can hemostatic signs be due to?
  55. When do we do screening tests for a hemostatic disorder?
    when we suspect a clot disorder
  56. What kind of controls can we use when doing screening tests for hemostatic disorders?
    normal animals in the hospital
  57. How many platelets are normal in an oil field?
     8 - 10
  58. What will make the platelet count appear low?
  59. When should we do a direct thrombocyte count?
    within 4 hours of collecting the blood or they will disappear
  60. Which species thrombocyte count is usually inaccurate when using an automated counter?
  61. At what platelet count do we usually see signs of hemostatic disorders?
    < 50,000
  62. What are the mechanisms of thrombocytopenia?  And what causes each one?
    • decreased production:  drugs, anaplasma platys, FeLV
    • increased destruction:  immune mediated, modified live virus, drugs
    • consumption/sequestration:  DIC, splenic torsion, sepsis
  63. What is sepsis?
    local or generalized invasion of the body by pathogenic microorganisms or their toxins
  64. How do we check thrombocyte morphology?
    check a blood smear
  65. What do we look for in thrombocyte morphology?
    • large platelets
    • schistocytes
    • organisms
  66. What causes large platelets?
    • megakaryocytic hyperplasia (young platelets)
    • a regenerative response
  67. What are schistocytes?
    rbc fragments
  68. When do we usually see schistocytes?
    in DIC or vascular neoplasia
  69. What is cyclic thrombocytopenia?
    thrombocytopenia that comes and goes
  70. What are the different tests we can do for hemostatic disorders?
    • bleeding time
    • clot retraction
    • activated clotting time
    • partial thromboplastin time (PTT)
    • prothrombin time (PT)
    • blood coagulation analyzers
  71. What kind of blade do we use for the bleeding time test?
  72. When is the bleeding test over?
    when a clot forms
  73. How do we do the buccal mucosal bleeding test?
    • cut a hairless area (gums work best)
    • gentle blotting with no pressure
    • note time until clot forms
  74. What are the normal times for a clot to form in a dog?  Cat?
    • dog:  1.7 - 4.2 min
    • cat:  1.4 - 2.4 min
  75. What does bleeding time evaluate?
    primary hemostasis
  76. The most common reason we see a bleeding defect is due to _____.  Most common type of _____ is _____.
    • thrombocytopenia
    • thrombocytopenia
    • immune mediated
  77. If there is a prolonged bleeding time then we know we have a problem with what?
    vessel wall
  78. What is clot retraction?
    crude test of platelet function
  79. How do we do a clot retraction test?
    • leave blood in a tube without anticoagulant
    • clot should retract from the wall of the tube within 1 hour
    • we consider it a problem if it takes more than 24 hours - suggests platelet malfunction
  80. How do we do an activated clotting time test?
    • must use a vaccutainer
    • avoid the first few drops of blood
    • fill a 2ml ACT tube
    • warm the tube and blood to body temperature
    • leave in the warmer for 50 second, and invert every 10 seconds
    • note the time the blood clots
  81. What is in the ACT tube?
    diatomaceous earth...dinosaurs :(
  82. How long should it take a dogs blood to clot during the activated clotting time test?  Cats?
    • dog:  60 - 110 seconds
    • cat:  50 - 75 seconds
  83. If an animal has thrombocytopenia what will happen during the activated clotting time test?
    will automatically be prolonged giving us false results
  84. What does partial thromboplastin time test?
    intrinsic/common pathways
  85. Which test is more sensitive, PTT or ACT?
  86. What does PTT stand for?
    partial thromboplastin time
  87. What time of plasma must we use for the PTT test and what tube do we use to get it?
    • citrated plasma
    • blue top tube (sodium citrate)
  88. What is PTT used to diagnose?
  89. Do we need to fill the sodium citrate tube completely when running the PTT test?  Why or why not?
    • yes
    • must have the appropriate ratio of blood to sodium citrate
  90. When should we run the PTT test?
    within 3-4 hours of collecting the blood
  91. What does the prothrombin time test for?
    • extrinsic/common pathways
    • tests for factor VII
  92. What does PT stand for?
    prothrombin test
  93. What kind of plasma is needed to run PT test?
    citrated plasma
  94. When should we run the PT test?
    within 2 hours of collecting blood
  95. What does PT mostly diagnose?
    coumarin toxicity and DIC
  96. What are the most common blood coagulation analyzers?
    • COAG Dx (formally SCA 2000)
    • VS Pro (Abaxis)
  97. What kind of test does the COAG DX (SCA 2000) run?
    • ACT
    • OSPT
    • APTT
  98. What does the COAG Dx (SCA 2000) evaulate?
    evaluates intrinsic, extrinsic, and common pathways
  99. What kind of tests does the VS Pro (Abaxis) run?
    • PT
    • PTT
  100. What is von Willebrand's disease?
    • an inherited bleeding disorder
    • deficiency of vW factor
  101. What is the vW factor?
    chemical that facilitates platelets attaching 
  102. What does the vW factor carry?
    factor VIII
  103. von Willebrand's disease has a deficiency of what?
    vW factor
  104. How do we test for vWf (vW factor)?
    • send out citrated plasma
    • separate immediately, freeze quickly
  105. Are there genetic tests available for von Willebrand's disease?
  106. What is DIC?
    massive stimulation of clotting mechanisms
  107. What are some clinical signs of DIC?
    • microthrombosis
    • bleeding
  108. What is usually the outcome of DIC?
    death usually occurs
  109. What are some common causes of DIC?
    • pancreatitis
    • heartworm disease
    • RMSF
    • ICH
    • FIP
    • feline panleukopenia
    • GDV
    • neoplasia
  110. How do we diagnose DIC?
    • initiating condition present
    • bleeding/organ failure (petechiae/ecchymoses)
    • TCP
    • all coagulation tests are prolonged
  111. What is hemophilia?
    unable to clot blood
  112. What are the two types of hemophilia?
    • hemophilia A
    • hemophilia B
  113. Is hemophilia inherited?
    yes, sex linked
  114. Which chromosome is hemophilia carried on?
  115. What type of deficiency does hemophilia A have?
    factor VIII
  116. What type of deficiency does hemophilia B have?
    factor IX
  117. What test is prolonged when we have a patient with hemophilia?
  118. What is coumarin toxicity?
  119. What does coumarin block?
    vitamin K
  120. What factor does coumarin toxicity lack?
    factor VII
  121. How is coumarin toxicity diagnosed?
    • history
    • prothrombin time is prolonged
  122. Which tests are normal with coumarin toxicity?
    • ACT
    • thrombocyte count
  123. What is in rodenticides that causes the calicum in an animal to increase?
  124. What are vascular disorders?
    disease of vessels
  125. What type of diseases are vascular disorders?
    • vasculities (FIP)
    • hyperadrenocortisim (cushings)
  126. How are vascular disorders diagnosed?
    • history
    • signs
    • eliminating other possibilities