THE APPLICATION OF A RAPID D-DIMER TEST IN SUSPECTED PULMONARY EMBOLUS

A prospective, consecutive series of plasma D-dimer (D-D) using a rapi d, sensitive, and semiquantitative latex agglutination test from 169 p atients clinically suspected of having acute pulmonary embolus (PE) wa s performed to determine its clinical utility in acute PE. All patient s had ventilation/perfusion (V/Q) scans and 20 patients (12%) subseque ntly had pulmonary arteriography (PAG). The 20 patients who subsequent ly had PAG were used to establish the predictive value(s). In 10 patie nts with normal D-D results, none had PE according to PAG. In 10 patie nts with abnormal D-D results, seven showed PE by PAG and three did no t show PE by PAG. The sensitivity, specificity, positive predictive va lues, and negative predictive values of the plasma D-D tests for acute PE based on PAG were 1.00, 0.77, 0.70, and 1.00, respectively. In nin e patients with indeterminate V/Q scans who had PAG, four had PE and t he D-D result was abnormal. Five of these patients did not have PE and the D-D result was abnormal in three and normal in two. Seventeen pat ients had high-probability V/Q scans, all of whom had abnormal D-D res ults. Only one had PAG that showed PE in this group. A normal D-D resu lt using a rapid latex agglutination method can effectively exclude th e diagnosis of acute PE. The negative predictive value of the rapid la tex agglutination method is as good as the more cumbersome enzyme-link ed immunosorbent assay methods. An abnormal result is nonspecific and is not useful in the diagnosis of acute PE. While some ''false positiv es'' did occur, there were no false-negative results. The best use of the D-D test is in the examination of the patient with indeterminate V /Q studies. We conclude that the D-D test can rapidly provide informat ion in determining whether a patient needs further angiographic studie s.