The Burden of Unnecessary Testing From a Regularly Ordered Laboratory Assay: Age-Adjusted d-Dimer Quality Improvement Study

Diagnosing acute pulmonary embolism (PE) involves clinical suspicion in combination with sequential diagnostic tests including d-dimer laboratory assays. Although the sensitivity of this assay is well validated and thoroughly tested, a false-positive result can lead to unnecessary and costly testing. The age-adjusted d-dimer (AADD) has been suggested in the literature to improve the usefulness of d-dimer cutoffs and safely decrease iodine and radiation exposure associated with definitively ruling out PE with computed tomographic angiography (CTA).(1) We present an internal retrospective review utilizing the novel AADD cutoff to rule out PE and evaluate the potential extent of unnecessary testing with CTA. Using the AADD cutoff would have led to a 21.2% reduction in computerized tomography pulmonary embolus protocol. This internal quality improvement study suggests that changing our institutional conventional d-dimer to the novel AADD would provide a superior quality and cost–benefit.