Activated Partial Thromboplastin Time (aPTT)

Coagulation

Normal Reference Ranges

Adult

30 - 40 seconds

Pediatric

30 - 40 seconds

Clinical Significance

Measures the intrinsic and common coagulation pathways. Primarily used to monitor unfractionated heparin therapy.

Causes of High

  • Heparin therapy
  • Hemophilia A or B
  • von Willebrand disease
  • Lupus anticoagulant
  • Severe liver disease

Causes of Low

  • Not clinically significant
  • Early stage DIC
  • Extensive cancer