Venous thromboembolic diseases: diagnosis, management and thrombophilia testing

Context

In venous thromboembolism (VTE), a blood clot forms in a vein, usually in the deep veins of the legs or pelvis. This is known as deep vein thrombosis, or DVT. The blood clot can dislodge and travel in the blood, particularly to the pulmonary arteries. This is known as pulmonary embolism (PE). The term 'VTE' includes both DVT and PE.

Failure to diagnose and treat VTE correctly can result in fatal PE, in which the blood clot blocks the blood supply to the lungs. However, diagnosis of VTE is not always straightforward. This guideline includes advice on the Wells score, D‑dimer measurement, ultrasound and radiological imaging. It also offers guidance on treating VTE, investigations for cancer in people with VTE and thrombophilia testing. The guideline covers adults with suspected or confirmed DVT or PE. It does not cover children or young people aged under 18, or women who are pregnant.

Since the publication of the updated guideline in 2020, new evidence has emerged that indicates higher risk of VTE and elevated D‑dimer levels in people with COVID‑19. In addition, a Healthcare Safety Investigation Branch (HSIB) report published in March 2022 reported difficulties in using the PERC for ruling out pulmonary embolism. This 2023 update includes updated recommendations in these areas.