Midterms Lab Test and Others

• aPTT


  Screens for factor deficiencies in the intrinsic and common pathway
• Prothrombin time


  • Tests for factor I, II, V, VII and X deficiency
  • Test of choice for monitoring anticoagulant therapy with vit K antagonist
• Whole blood clot lysis time


  • End result: dissolving of clot
  • Clot should remain intact for approximately 48hrs at 37C
• Euglobulin lysis time


  • A screening test for the measurement of fibrinolytic activity
  • Principle: euglobulins precipitate when plasma is diluted with water and acidified
• Protamine sulfate dilution test


  • Detects the presence of fibrin monomers in the plasma
  • Distinguish primary and secondary fibrinolysis
  • Principle: paracoagulation
• Ethanol gelation test


  • Detects the presence of fibrin monomers
  • Principle: 50% ethanol causes soluble fibrin monomer to dissociate, resulting in polymerization of monomers and subsequent gel formation
• Latex D-dimer assay


  • D-dimer ~ specific fragment from fibrin degradation
  • Measures fibrinolysis
  • Positive in DIC
• Mixing studies


  • Follow up to an abnormal PT or aPTT
  • Test is repeated on 1:1 mixture of px plasma and normal plasma
  • Px with factor deficiency: time will be corrected because normal plasma supplies missing factor
  • If time is not corrected: presence of an inhibitor
• Unfractionated Heparin


  • Catalyzes inhibition of thrombin, Xa & IXa by antithrombin
  • Administration: IV
  • Effect: immediate
• Warfarin


  • Vitamin K antagonist
  • Administration: Oral
  • Effect: slow acting