Hematology Quiz 9

• What is necessary to control bleeding?

  1. Availability and activity of platelets
  2. Size and ability of the vessel to contract
  3. Pressure around the vessel and surrounding tissues
• What Ion is required for the coagulation cascade to work?

  Ca++
• What is petechiae?

  Tiny bruising/ brown, purple spots due to bleeding under the skin, may be in a small area due to minor trauma or widespread due to blood clotting disorder.
• What can be done about a Coumadin overdose?

  Vitamin K
• What is the coagulation process?

  1. Reaction of the blood vessels (Vasoconstriction)
  2. Formation of the platelet plug
  3. Reactions of the coagulation factors (clotting)
• Platelet aggregation


  When platelets bind to one another
• Platelet Adhesion

  When platelets bind to a vessel wall
• Prothrombin Test (PT)

  Factor II,V,VII,X
• Activated partial thromboplastin time (APTT)

  Factor VIII, IX, XI, XII
• When is a platelet count considered critical and can cause bleeding?


  <50,000
• What is the end result of most coagulation tests?

  Fibrin clot
• What is fibrinolysis?


  Fiber degradation
• What can aspirin do to a bleeding time result?


  Thins blood therefore increasing bleeding time
• Why is heparin used?

  to prevent blood clotting in patients with certain conditions/diseases
• What does INR stands for?

  International Normalized Ratio
• What natural things in the body can inhibit coagulation?

  Protein C, Antithrombin III, feedback inhibition
• Inherited coagulation disorders generally result in what?

  Deficiency of one factor
• What type of therapy is a patient on if we are testing a PT OR PTT?

  PT- Coumadin

  PTT- Heparin
• Define thrombocythemia.

  Platelet function is abnormal and overproduces.
• Define hemophilia 


  A diseases involving inability to blood clot
• Protime 


  Monitors factors in extrinsic system
• APTT


  Monitors factors in intrinsic system
• Bleeding time, Ivy method

  Most common. The patients ARM is positioned at the level of the heart and a blood pressure cuff inflated to 40mmHg. After alcohol cleansing, a standardized device is utilized to make a 10mm long and 1mm deep incision on the volar forearm. Using a timer the blood is blotted twice a minute.
• Bleeding Time, Duke method

  patient is pricked with a special needle or lancet, preferably on the EARLOBE, after having been swabbed with alcohol. The prick is about 3-4 mm deep. The patient then wipes the blood every 30 seconds with a filter paper. The test ceases when bleeding ceases.
• Platelet function analysis 


  alternative to bleeding time, times how long blood clots in tube using different activating substance.
• D-dimer

  tests that measures fibrin degradation AKA fibrinolysis
• Intrinsic (pathway) 


  VIII, IX, XI,XII
• Extrinsic

  III, VII
• Common pathway

  I,II,V,X,XIII
• Needed in all pathways

  Calcium