Accuracy of the Clinical Diagnosis of Pulmonary Embolism

The accuracy of the clinical diagnosis of pulmonary embolism was evaluated in 78 patients. The clinical diagnosis of a pulmonary embolus derived from history, symptoms, physical findings, electrocardiogram, laboratory enzymes, roentgenogram of the chest, and isotope lung scan was compared to that established by pulmonary angiography. Pulmonary emboli were demonstrated in only 32 (41%) of the 78 patients studied. Reasons for illness in the 46 (59%) patients without emboli were chiefly atelectasis, congestive heart-failure, and pneumonitis. Except for phlebitis, no element of the history clearly favored or opposed emboli. Neither symptoms, physical findings, ECG, serum enzymes, nor chest roentgenography were able to distinguish patients with embolism. The isotope lung scan could accurately detect defects in lung perfusion but was unable to differentiate causes. Pulmonary angiography remains the most objective and definitive diagnostic method.