II. Indication

  1. Bleeding Disorder
    1. Replaced by von specific tests (Willebrand Factor Activity, Von Willebrand Factor Antigen, Factor VIII Level)
  2. Historical indications
    1. Replaced Bleeding Time to assess platelet function
    2. Personal or Family History of easy Bruising or bleeding
      1. Epistaxis
      2. Menorrhagia
      3. Post-operative bleeding

III. Protocol: Sample

  1. Citrate anticoagulated whole blood

IV. Mechanism

  1. Rapid quantitation of platelet function for hemostasis
  2. Blood passed through high shear flow system
  3. System measures time to occlude membrane
  4. Blood is tested with two membranes
    1. Collagen/Epinephrine (CEPI) membrane
    2. Collagen/Adenosine Diphosphate (CADP) membrane specific for Aspirin

V. Interpretation: Normal

  1. CEPI closure <175

VI. Causes: Abnormal (prolonged closure time)

  1. Von Willebrand's Disease
  2. Glanzmann's Thrombasthenia
  3. Thrombasthenia
  4. Thrombocytopenia with Platelet Count <100,000/mm3
  5. Anemia with Hematocrit <35%
  6. Aspirin (will prolong only the CEPI membrane time)

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