A highly sensitive ELISA D-dimer increases testing but not diagnosis of pulmonary embolism

Objectives: To determine the effect of introducing a rapid enzyme-linked immunosorbent assay (ELISA) D-dimer on the percentage of emergency department (ED) patients evaluated for pulmonary embolism (PE), the use of associated laboratory testing, pulmonary vascular imaging, and the diagnoses of PE. Methods: Patients evaluated for PE during three 120-day periods were enrolled: immediately before (period 1), immediately after (period 2), and one year after the introduction of a rapid ELISA D-dimer in the hospital. The frequency of ED patients evaluated for PE with any test, with D-dimer testing, and with pulmonary vascular imaging and the frequency or PE diagnosis during each time period were determined. Results: The percentage of patients evaluated for PE nearly doubled; from 1.36% (328/24,101) in period I to 2.58% (654/25,318) in period 2 and 2.42% (583/24,093) in period 3. The percentage of patients Who underwent D-dimer testing increased more than fourfold; from 0.39% (93/24,101) in period 1 to 1.83%, (464/25,318) in period 2 and 1.77% (427/24,093) in period 3. The percentage of patients who underwent pulmonary vascular imaging increased from 1.02% (247/24,101) in period 1 to 1.36% (344/25,318) in period 2 and to 1.39% (334/24,093) in period 3. There was no difference in the percentage of patients diagnosed as having PE in period 1 (0.20%, [47/24,101]), period 2 (0.27% 169/25,3181), and period 3 (0.24% [58/24,093]). Conclusions: In the study's academic ED, introduction of ELISA D-dimer testing was accompanied by an increase in PE evaluations, D-dimer testing, and pulmonary vascular imaging; there was no observed change in the rate of PE diagnosis.