Deep venous thrombosis: prediction by D-dimer?

The utility of D-dimer as an inexpensive, noninvasive method of diagnosing deep venous thrombosis (DVT) is debated. We sought to determine whether a qualitative D-dimer assay would have a high correlation with DVT in 65 hospitalized patients who were randomly referred for diagnosis of DVT by venous duplex and duplex Doppler ultrasonography. Patients were excluded from the study if they had any inflammatory, infectious, or malignant condition associated with elevation of D-dimer. The mean level of D-dimer in patients with DVT (16 of 65 patients) was 5,141 ng/mL, compared with 3,024 ng/mL in those without DVT, but there was considerable overlap between the two groups. No patients with a D-dimer level < 2,000 ng/mL had DVT. We conclude that the qualitative D-dimer assay is an excellent exclusionary test for DVT at levels less than 2,000 ng/mL. Limitations of the D-dimer assay and cost-effective issues are discussed.