D-dimer levels < 250 ng/mL after oral anticoagulation predicted a low risk for recurrent venous thromboembolism.

A s s e s s m e n t o f p r o g n o s t i c f a c t o r s 3 weeks after stopping OAT, laboratory testing was done to determine the levels of D-dimer (measured by an enzyme-linked immunoassay [Asserachrom D-dimer, Boehringer Mannheim, Mannheim, Germany]), antithrombin, protein C, protein S, factor VIII, the lupus anticoagulant, factor V Leiden, and factor II G20210A. Levels of D-dimer were classified as < 250, 250 to 499, 500 to 749, and ≥ 750 ng/mL. Associations between the prognostic factors and times to recurrence were assessed using univariate and multivariate survival analysis.