Bedside diagnosis of pulmonary embolism.

Pulmonary embolism (PE) is often underdiagnosed, mainly because it is not thought of. Its clinical signs are riot highly specific and are encountered in a wide range of pulmonary diseases. Certain symptoms and signs, particularly when combined, are suggestive of PE: unexplained dypsnea, pleuretic pain with or without hemoptysis, tachypnea, etc, but they are not pathognomonic. Routine laboratory investigations such as arterial blood gas analysis, total blood cell count, serum LDH, etc.., contribute poorly to making the diagnosis. D-dimers are fibrin degradation products. It has now been made possible to rule out PE in almost 20% of suspected cases, when plasma D-dimers levels are lower than 500 ng/ml, using the ELISA technique, with a very high sensitivity rare (98%). On the other hand, their specificity and positive predictive value are low (<50%) and under ilo circumstances should their measurement be used to confirm the diagnosis of PE. This test is time-consuming, but new faster techniques seem to be promising.