Ordieres-Ortega L, et al. - Since the value of D-dimer testing for the diagnosis of thrombosis in unusual sites is not properly established and evidence is scarce. Researchers conducted a systematic review of the literature. This study was conducted to search MEDLINE and Cochrane Library for papers published in the last 10 years involving different presentations of thrombosis in unusual sites. Between January 1, 2008, and December 31, 2018, 23 articles were enrolled, including a total of 3,378 individuals with thrombosis in unusual sites (upper extremity deep vein thrombosis, cerebral vein thrombosis, and splanchnic vein thrombosis). They applied the Newcastle-Ottawa scale to evaluate the quality of the studies. For the diagnosis of thrombosis, D-dimer testing should not be currently recommended in unusual sites as a first-line diagnostic tool. The improvement of algorithms combining biomarkers such as D-dimer and clinical decision tools could better the diagnosis.