Activated Partial Thromboplastin Time (APTT)

How to Cite This Chapter: Don-Wauchope A, Chetty VT, Ivica J, Kavsak P, Khan WI, Lafreniere M, Nouri K, Solnica B. Activated Partial Thromboplastin Time (aPTT). McMaster Textbook of Internal Medicine. Kraków: Medycyna Praktyczna. Accessed May 26, 2024.
Last Updated: May 9, 2022
Last Reviewed: May 9, 2022
Chapter Information

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)

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