Pulmonary embolism despite negative ELISA D-dimer: a case report.

Pulmonary embolus (PE) can be fatal, but is often treatable if recognized early. Unfortunately, the clinical presentation of PE is often variable and misleading. The D-dimer assay has recently come into favor as a method to exclude PE; however, this test has an acceptable safety margin only in low-risk populations. What is unclear is the exact composition of this low risk population. This is the report of a 26-year-old woman with over 2 weeks of chest pain and intermittent dyspnea. The patient was initially seen in the Emergency Department (ED) and hospitalized. She returned to the ED 2 weeks later with similar symptoms. Although enzyme-linked immunosorbent assay (ELISA) D-dimer assays were normal on the initial and subsequent ED visits, pulmonary embolism (PE) was diagnosed by computed tomography scan on the second visit. This report highlights the risk of misdiagnosing PE if relying solely on ELISA D-dimer for exclusion. The approach to PE should include a measure of clinical probability. This report documents the presentation of PE despite having two unremarkable ELISA D-dimer measurements, and highlights the importance of clinical suspicion.