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For further information, see CMDT Part 14-09: Acquired Disorders of Coagulation

Key Features

  • Lupus anticoagulants prolong activated partial thromboplastin time (aPTT) by interfering with interactions between the clotting cascade and the phospholipid surface on which they function

  • Antibodies may also interfere with factor II activity (rare); this small subset of patients are at risk for bleeding

  • They were so named because of their early identification in patients with systemic lupus and other connective tissue diseases

  • However, they may occur with increased frequency in individuals with underlying infection, inflammation, or malignancy

  • Can occur in asymptomatic individuals in the general population

Clinical Findings

  • No bleeding

  • Increased risk of thrombosis and recurrent spontaneous abortions


  • Prolonged aPTT that does not correct completely on mixing but that normalizes with excessive phospholipid

  • Specialized testing can confirm presence of lupus anticoagulant

    • Positive hexagonal phase phospholipid neutralization assay

    • Prolonged dilute Russell viper venom time

    • Positive platelet neutralization assays


  • No specific treatment necessary

  • Anticoagulation in standard doses for patients with thromboses, aiming for INR of 2.0–3.0

  • Because of artificially prolonged PTT, unfractionated heparin therapy is difficult to monitor; thus, weight-based low-molecular-weight heparin is preferred

  • Prophylaxis during pregnancy should be with low-molecular-weight heparin

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