Bedside diagnosis of pulmonary embolism.

Pulmonary embolism (PE) is often underdiagnosed, mainly because it is not t hought of. Its clinical signs are riot highly specific and are encountered in a wide range of pulmonary diseases. Certain symptoms and signs, particul arly when combined, are suggestive of PE: unexplained dypsnea, pleuretic pa in with or without hemoptysis, tachypnea, etc, but they are not pathognomon ic. Routine laboratory investigations such as arterial blood gas analysis, tota l blood cell count, serum LDH, etc.., contribute poorly to making the diagn osis. D-dimers are fibrin degradation products. It has now been made possib le to rule out PE in almost 20% of suspected cases, when plasma D-dimers le vels 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 p redictive value are low (<50%) and under ilo circumstances should their mea surement be used to confirm the diagnosis of PE. This test is time-consuming, but new faster techniques seem to be promising .