What laboratory test is often used to diagnose pulmonary embolism?

The D-dimer test is a valuable diagnostic tool in the evaluation of pulmonary embolism (PE). It measures the levels of D-dimer, a fibrin degradation product that is present when a blood clot dissolves in the body. Elevated levels of D-dimer can suggest the presence of an abnormal clotting process, which may indicate conditions such as thrombosis or pulmonary embolism.

In the context of diagnosing pulmonary embolism, a D-dimer test is typically used as a first step, especially in patients with a low to moderate pre-test probability of PE. A negative result can help rule out PE, avoiding the need for more invasive imaging studies. However, elevated levels alone are not definitive for PE, and further investigation is usually required.

Other tests have their uses but are not as effective as a first-line screening tool for pulmonary embolism. A chest X-ray may help rule out other conditions but does not directly diagnose PE. A CT scan of the abdomen is not primarily focused on the pulmonary vasculature, and a complete blood count (CBC) provides general information about blood components but does not assess specific indicators for thrombosis or embolism. Thus, the D-dimer test stands out as a more targeted and relevant laboratory test for