Activated Partial Thromboplastin Time (APTT)

For a brief introduction and guide to abbreviations, see Laboratory Tests: General Remarks.

Analyte [material]

Activated partial thromboplastin time (aPTT) [P]

Reference range, target level, or decision threshold

26-40 s (depending on reagents used)!!!; LD

Interpretation of results

↑ Congenital or acquired deficiencies of fibrinogen and/or factors II, V, VIII (eg, hemophilia, von Willebrand disease), IX, XI, or XII; acquired inhibitors against factors VIII (acquired hemophilia A), IX, XI, or XII, high-molecular weight kininogen, or prekallikrein; vitamin K deficiency; liver diseases; DIC; hemodilution; lupus anticoagulant; anticoagulants (UFH, VKAs, direct thrombin inhibitors, direct factor Xa inhibitors)