AGE-ADJUSTED D-DIMER IN SUSPECTED PULMONARY EMBOLISM: SAFETY AND REDUCTION IN CT PULMONARY ANGIOGRAPHY

Abstract

A fixed D-dimer threshold becomes less specific with increasing age, leading many older adults with suspected pulmonary embolism to undergo imaging despite the absence of thromboembolism. Age adjustment aims to preserve safe exclusion while improving the usefulness of a negative result. This structured narrative review synthesizes PubMed-indexed management studies, diagnostic accuracy analyses, evidence syntheses, and guidelines identified through focused searches and targeted retrieval through October 8, 2026. In appropriately selected adults with non-high pretest probability, the usual threshold is 500 μg/L in fibrinogen equivalent units up to age 50 and age multiplied by 10 μg/L thereafter. In ADJUST-PE, the three-month thromboembolic failure rate among patients with D-dimer above 500 μg/L but below the age-adjusted threshold was 0.3%, with a 95% confidence interval of 0.1% to 1.7%. Among eligible patients aged at least 75 years, the proportion in whom pulmonary embolism could be excluded using D-dimer increased from 6.4% to 29.7%. RELAX-PE supported safety in routine outpatient care, while individual-patient meta-analysis demonstrated a smaller average efficiency gain across broader populations. These benefits depend on correct assessment of clinical probability, a sufficiently sensitive validated assay, and accurate interpretation of laboratory units. Evidence from combined YEARS and age-adjusted strategies should not be attributed to age adjustment alone. Age-adjusted D-dimer can safely reduce the need for CT pulmonary angiography in suitable patients, particularly older outpatients, while high clinical probability, hemodynamic instability, anticoagulant exposure, and assay uncertainty require different diagnostic considerations.