PULMONARY-EMBOLISM - EFFICACY OF D-DIMER AND THROMBIN-ANTITHROMBIN ILL COMPLEX DETERMINATIONS AS SCREENING-TESTS BEFORE LUNG-SCANNING

The aim of the study was to evaluate if D-dimer and thrombin-antithrombin III complex determinations in patients with clinically suspected pulmonary embolism create a discrimination between patients to be further investigated with lung scanning and those who should be investigated for other diseases mimicking pulmonary embolism. The Data-Fi Dimertest Latex Assay, MAbCO Dimertest EIA, and TAT EIA were performed in 100 consecutive patients (26 percent outpatients) who were sent to our institution for lung scanning by their attending physicians because of clinically suspected pulmonary embolism. The D-dimer Latex Assay was positive (> 500 ng/ml) in 12 (48.0 percent) of 25 patients with high probability of pulmonary embolism and in one (11.1 percent) of nine with intermediate probability, respectively. Only one patient (1.5 percent) with a normal scan had a positive latex assay, presumably due to inapparent bleeding after a computed tomographic (CT)-guided liver biopsy. Referring to 120 ng/ml as upper limit of normal (mean +/- 2 SD of healthy controls), the D-dimer enzyme immunoassay (EIA) was positive in 21 (84.0 percent) of 25 patients with high probability, in six (66.7 percent) of nine patients with intermediate probability, and in 40 (60.6 percent) of 66 patients with normal/flow probability of pulmonary embolism, respectively. The TAT EIA was positive (> mean +/- 2 SD of healthy controls = 3.53 ng/ml) in 18 (72.0 percent) of 25 patients with high probability, in five (55.6 percent) of nine patients with intermediate probability and in 16 (24.2 percent) of 66 patients with normal/low probability of pulmonary embolism. A normal result in one of these hemostaseologic tests did not predict a low probability of pulmonary embolism after lung scanning. Thus, it is not justified to exclude patients with clinically suspected pulmonary embolism from further investigation by lung scanning because of a normal result in one of these tests.