The place of D-dimer testing in an integrated approach of patients suspected of pulmonary embolism.

When a patient is suspected of having pulmonary embolism (PE), the first procedure performed in most institutions is lung scintigraphy. Here we propose an alternative diagnostic strategy based on the following sequential combination of procedures: clinical assessment, D-dimer measurement, ultrasonography of lower limbs, and lung scan. This integrated approach may rule out PE in the majority of outpatients suspected of PE and permits district hospitals without lung-scan facilities to manage approximately 50% of outpatients without referral. D-dimer alone will exclude PE in about 30% of patients at low cost. This stepwise strategy is especially useful because only 20-35% of patients suspected of PE really have the disease. Thus, in the majority of patients, ruling out the disease has replaced ruling in the disease.