The diagnosis of pulmonary embolism despite a negative D-dimer assay: the importance of individualised clinical assessment and other investigations

Pulmonary embolism is an important differential diagnosis in the work up of patients presenting with chest pain and respiratory symptoms. Left untreated, it carries a high mortality. Pulmonary embolism presents a diagnostic challenge as the clinical presentation varies widely. Hospitals in the United Kingdom frequently use the validated D-dimer assay as an initial ‘rule-out’ test for low-risk patients. We present the case of a 69-year-old woman, presenting with chest pain and cough. She was deemed low-risk for pulmonary embolism using validated scoring systems and had a negative D-dimer assay, however clinical suspicion and chest X-ray findings lead to further investigation with computed tomography pulmonary angiography. This revealed a suspected pulmonary infarct, and the diagnosis of pulmonary embolism was made. This report highlights that while the D-dimer assay and Wells score are useful tools in the work-up for pulmonary embolism, they should not replace careful clinical assessment. We also explore X-ray findings pertinent to this case and their association with pulmonary embolism.