Venous thromboembolism (VTE), which includes blood clots in the leg (DVT) and lungs (pulmonary embolism), is a common reason people come to A&E. VTE can cause serious harm or death but is difficult to diagnose. Doctors currently rely on a blood test (D-dimer) combined with a symptom-based score to decide who needs further scanning. This approach is reasonably safe, but it isn’t perfect: most patients (around 80 to 90%) sent for scans turn out not to have a clot, meaning many people are exposed to unnecessary tests, including those involving radiation.

Researchers have proposed several newer scoring methods that might reduce the number of people needing scans, without missing more cases of VTE. However, these methods haven’t been properly tested across UK hospitals, so it isn’t yet known whether they are safe and effective enough to use routinely.

As part of this study we will collect anonymised patient data from routine medical records such as age, sex, components of clinical risk scores and results of investigations.

We will also be collecting some data about how each acute or emergency site manages patients who present with symptoms concerning for VTE.

There is currently insufficient evidence to recommend newer diagnostic strategies for VTE and no large scale UK studies of these patients. This study will help us understand the current standard of care, and compare this with the estimated safety and efficiency of alternative strategies.

This will add to the evidence base that clinicians use on a daily basis to decide how to look after these patients and help inform a definitive future clinical trial.

The final outcomes from the DAVE study will be communicated via presentations in scientific meetings and by peer reviewed publications.

We will aim to publish the results approximately 12 months after completion. We may discuss interim results at academic conferences prior to this.