Which laboratory finding is commonly elevated in acute pulmonary embolism and used in initial assessment?

Which laboratory finding is commonly elevated in acute pulmonary embolism and used in initial assessment?

• A. D-dimer
• B. Troponin
• C. ESR
• D. AST

Answer: (A)

D-dimer is a fibrin degradation product that rises when there is clot formation and breakdown in the body. In acute pulmonary embolism, a thrombus forms in the pulmonary arteries and is broken down by the body’s fibrinolytic system, releasing D-dimer. Because this marker is highly sensitive for the presence of clot, it’s useful in the initial assessment to help rule out PE in patients with low pretest probability. A negative D-dimer makes PE unlikely, potentially avoiding imaging. However, a positive result isn’t specific to PE—many conditions can raise D-dimer—so it prompts further imaging, such as CT pulmonary angiography, rather than diagnosing PE on its own. Other options don’t fit as well for initial assessment: troponin can be elevated due to right heart strain from PE and has prognostic value but isn’t a screening tool for diagnosis; ESR and AST are nonspecific and not relied upon to evaluate for PE.

D-dimer is a fibrin degradation product that rises when there is clot formation and breakdown in the body. In acute pulmonary embolism, a thrombus forms in the pulmonary arteries and is broken down by the body’s fibrinolytic system, releasing D-dimer. Because this marker is highly sensitive for the presence of clot, it’s useful in the initial assessment to help rule out PE in patients with low pretest probability. A negative D-dimer makes PE unlikely, potentially avoiding imaging. However, a positive result isn’t specific to PE—many conditions can raise D-dimer—so it prompts further imaging, such as CT pulmonary angiography, rather than diagnosing PE on its own.

Other options don’t fit as well for initial assessment: troponin can be elevated due to right heart strain from PE and has prognostic value but isn’t a screening tool for diagnosis; ESR and AST are nonspecific and not relied upon to evaluate for PE.