Lab

Partial Thromboplastin Time

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Partial Thromboplastin Time, PTT

  • See Also
  1. Prothrombin Time
  2. Thrombin Time
  3. Whole Blood Clotting Time
  4. Clotting Pathway
  5. Intrinsic Clotting Pathway
  6. Extrinsic Clotting Pathway
  7. Common Clotting Pathway
  8. Bleeding Disorder
  • Background
  1. Evaluates Intrinsic Clotting Pathway integrity
  2. Plasma collected in a tube containing citrate, which binds Calcium and prevents initial clotting
  3. Calcium is added back to plasma, and time to clotting is measured
  • Labs
  • Normal
  1. Range: 25-41 sec
  • Causes
  • Increased
  1. Heparin
  2. Warfarin (Coumadin)
  3. Thrombolytics
  4. Clotting Factor deficiency
    1. Factor I Deficiency
    2. Factor II Deficiency
    3. Factor V Deficiency
    4. Factor VIII Deficiency (Hemophilia A)
    5. Factor IX Deficiency (Hemophilia B)
    6. Factor X Deficiency
    7. Factor XI Deficiency
    8. Factor XII Deficiency
  5. Liver disease
  6. Vitamin K Deficiency
  7. Disseminated Intravascular Coagulation (DIC)
  8. Circulating Anticoagulants or specific factor inhibitor
    1. Penicillin reaction
    2. Rheumatoid Factor