D-dimer testing is currently considered a cornerstone in the diagnostic approach of patients with suspected venous thromboembolism (VTE) across different health-care settings, including the emergency department (ED). Nevertheless, inappropriate or incorrect activities developing throughout the total testing process may substantially impair the clinical usefulness of this test and delay or even challenge the fast rule out or diagnosis of VTE. The leading problem of D-dimer is represented by the poor specificity for diagnosing VTE, wherein a minority of patients with a positive D-dimer are finally diagnosed with VTE, and even more importantly, the specificity further decreases with ageing, thus contributing to increase the overcrowding in short stay units such as the ED. Due to the large heterogeneity that characterizes the use of D-dimer in the emergency room, three Italian societies of laboratory medicine (Italian Committee for Standardization of Hematology and Laboratory Methods, Italian Society of Clinical Biochemistry and Molecular Biology, and Italian Society of Laboratory Medicine), along with the Academy of Emergency Medicine and Care, have developed a consensus document about the use of D-dimer testing for diagnostics of patients with suspected VTE in this health-care setting. The evidence-based indications contained in this document will cover the leading preanalytical, analytical, and postanalytical issues that may impair the clinical efficacy of D-dimer testing in the ED.