What diagnostic test has been considered the "gold standard" for diagnosing venous thromboembolism?

The ascending venogram is considered the "gold standard" for diagnosing venous thromboembolism (VTE), particularly deep vein thrombosis (DVT). This diagnostic test involves injecting a contrast dye into a vein and then taking X-ray images to visualize the blood flow and identify any blockages caused by clots. It provides a clear and direct assessment of the venous system, thus allowing for definitive diagnosis.

While other tests like ultrasound and D-dimer are valuable in the diagnostic process, ascending venography is more definitive as it directly visualizes the presence of thrombus. Ultrasound is a common and non-invasive first-line test, but it may not detect all DVTs, especially in certain anatomical areas. D-dimer testing is useful for ruling out VTE but is not specific enough to serve as a standalone diagnostic tool. Consequently, ascending venography remains a crucial tool for accurate diagnosis when needed.