The DESTINY Study

The use of D-dimer testing in primary care as a diagnostic tool for Deep Vein Thrombosis (DVT) is based on the test’s ability to detect the presence of fibrin degradation products in the blood (D-dimer), which are elevated when blood clots are actively forming and breaking down. DVT is a serious condition where a blood clot forms in a deep vein, usually in the lower leg, thigh, or pelvis, but clots can occur in other parts of the body.

D-dimer levels are usually undetectable or very low in healthy individuals. An elevated D-dimer level might indicate the presence of an abnormally high level of fibrinolysis, which can be due to several conditions, including DVT and pulmonary embolism (PE).

In the context of primary care, D-dimer testing is particularly valuable for its high negative predictive value. This means that a low or normal D-dimer level is a strong indicator that a DVT is not present, which can be reassuring and reduce the need for more invasive and expensive tests like venography or ultrasound in patients with a low probability of thrombosis.

The use of D-dimer testing as part of a diagnostic algorithm that includes clinical assessment ad pre-test probability scoring systems, such as the Wells score for DVT, can improve the test’s specificity. Patients with a low pre-test probability and a negative D-dimer test can safely be ruled out for DVT, reducing the burden on healthcare resources and the patient’s exposure to potentially harmful investigations.