Can plasma D-dimer predict the result of a ventilation-perfusion scan?

The use of plasma D-dimer assay has been advocated for the exclusion of pulmonary embolism. We retrospectively looked at 840 patients in whom both ventilation-perfusion scan and D-dimer assay were performed within 48 h. The negative predictive value of a negative D-dimer assay was 96% for emergency admissions and 98% for inpatients. We present the cases of two patients with negative D-dimer assay results who had a high-probability lung scan, and we have found a further three patients with negative D-dimer assay results who had an intermediate-probability lung scan.