Integrating Clinical, Laboratory and Imaging Tests in the Diagnosis of Pulmonary Embolism

A diagnosis of an acute pulmonary embolism requires evaluation of risk factors and integration of clinical, laboratory and imaging tests. Clinical probability is determined using a validated prediction score, such as modified Wells or revised Geneva scores. D-dimer testing is recommended in patients with low or intermediate clinical probability, but should not be performed in high probability patients. A “PERC” approach (“pulmonary embolism rule-out criteria”) is recommended in low risk patients. Use of age adjusted D-dimer cut-off and variable D-dimer cut-off according to presence of risk factors, reduces the number of unnecessary imaging tests. High clinical probability patients and those with elevated D-dimer values should perform an imaging study, usually computerized tomography pulmonary angiography (CTPA) or a radionuclide ventilation/perfusion scan.