Fibrinogen/fibrin degradation products in the diagnosis of pulmonary embolism in critically ill patients

The concentration of fibrinogen/fibrin degradation products (FDP/fdp) was measured using a direct latex agglutination tests in 40 critically ill patients with pulmonary arteriography and possible acute pulmonary embolism. All of them were admitted with signs of severe heart and/or respiratory insufficiency, and 12 (30%) of the patients required mechanical ventilation. The concentration of FDP/fdp was significantly higher in 28 of 29 patients with positive arteriography (mean 145 microgram/ml), that in those whose arteriography was negative (in every cases the FDP/fdp level was lower than 10 microgram/ml). To help differentiate pulmonary embolism from other acute heart or pulmonary diseases, the authors measured the FDP/fdp in 10 patients with bacterial pneumonia, 24 patients with acute myocardial infarction, 4 patients with extrinsic asthma, and 18 normal control subjects. The authors found high levels of FDP/fdp (more than 10 microgram/ml) in only 2 patients with pneumonia and in 6 with myocardial infarction. In no case was the level of FDP/fdp higher than 40 microgram/ml. On the other hand, in patients with pulmonary embolism, 23 (79%) had levels higher than 40 microgram/ml. The study indicates that this test is a helpful screening method for pulmonary embolism, especially in situations where other emergency diagnosis tests are inconclusive or impractical; it also provides justification for beginning anticoagulant therapy and for recommending pulmonary arteriography.