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Elevations in PT or aPTT assays

PT and/or aPTT may be prolonged for a number of reasons.

Prolonged PT causes include:

  • Warfarin therapy
  • Liver disease
  • Disseminated intravascular coagulation (DIC)
  • Vitamin K deficiency
  • Liver conditions such as cirrhosis or hepatitis
  • Inadequate level of Factors I, II, V, VII, and/or X

Prolonged aPTT causes include:

  • Presence of heparin
  • Liver disease, other liver conditions
  • Vitamin K deficiency
  • Hemophilias
  • DIC
  • von Willebrand disease
  • Lupus anticoagulant
  • Inadequate levels of Factors I, II, V, VIII, IX, X, XI, and/or XII