Because the signs and symptoms of deep venous thrombosis and pulmonary embolism are common but non-specific, they often present a diagnostic challenge. Both underdiagnosis and overdiagnosis are associated with substantial morbidity and mortality.

D-dimers are fibrin degradation products resulting from endogenous fibrinolysis associated with intravascular thrombosis. A non-specific increase in D-dimer concentration is seen in many situations, precluding its use for diagnosing venous thromboembolism (VTE). However, a low D-dimer concentration is thought to rule out the presence of circulating fibrin and therefore VTE. Early enzyme linked immunosorbent assay D-dimer tests took a long time to do, limiting their usefulness in acute care. Second generation assays provide results within an hour, and point of care tests produce results within 10-15 minutes.

In the linked systematic review and meta-analysis (doi:10.1136/bmj.b2990), Geersing and colleagues analysed the diagnostic performances of several qualitative and quantitative D-dimer tests used at the point of care.1 They found that quantitative tests perform better than qualitative ones, but …