A Retrospective Study of Adult and Pediatric D‐Dimer Tests to Identify Opportunities for Improved Utilization

INTRODUCTION: D-dimers are produced by lysis of cross-linked fibrin. In children, D-dimer testing is used to evaluate disseminated intravascular coagulation (DIC) and some inflammatory states, but its use is not validated for screening or ruling out suspected venous thromboembolic events (VTE). In adults, D-dimers are used to evaluate DIC, and a low D-dimer level is used to exclude VTE in patients when combined with a low or moderate probability of VTE. METHODS: To assess D-dimer utilization and opportunities for improvement, we conducted a retrospective, consecutive-case cohort study (with ethics approval) of patients who had D-dimer tests at Hamilton hospitals, from 06/2022 to 05/2023. RESULTS: D-dimer levels were evaluated for 175 children and 200 adults (respective results, children/adults: median ages: 12/63, ranges 0-17/18-94 years), and an overlapping cohort of 99 consecutive persons with ≥ 5 D-dimer determinations. Most patients had D-dimer tests in emergency departments (60%/62%) and elevated D-dimer levels (55%/61%). Reasons for D-dimer assessment included: suspected VTE (50%/70%), DIC (17%/3.5%), childhood inflammatory conditions (23%/0%), and "off-label" uses (e.g., arterial thrombosis assessment; 5%/22%). VTE likelihood and DIC scores were rarely documented. Patients with multiple tests accounted for 15% of D-dimer workload. Among patients with multiple tests for DIC, most had overt DIC on initial assessment, with declining D-dimer levels over 10-14 days, including patients who died. CONCLUSION: VTE and DIC assessment was the most common reason for D-dimer assessments for children and adults. Quality improvement initiatives are needed to improve relevant clinical VTE and DIC score documentation and D-dimer test utilization.