Background: Hemoptysis is not common in pulmonary embolism (PE) and lacks specificity for its diagnosis. However, this item is present in different validated scores that estimate the clinical probability of PE. The relevance of this item in clinical decision rules (CDRs) is not clearly established. Objective:The aim of this study was to evaluate the impact of removing the "hemoptysis" item from the PERC, YEARS, and PEGeD CDR in patients with low clinical probability of PE.Design: This was a post hoc analysis of two European prospective cohorts, which included 2968 patients presenting to the ED with a low clinical probability of PE (PROPER and PERCEPIC) and a 3-month follow-up. The primary endpoint was the false-negative rate of a CDR score without the hemoptysis item. Secondary endpoints included the potential reduction of chest imaging if the item hemoptysis was to be removed and risk stratification of the Geneva and Wells scores without the hemoptysis item.Results: Of 2968 patients included (mean ± SD age 46 ± 18 years, 53% female), 87 patients (3%) had a PE diagnosed at 3 months. A total of 2908 were followed-up at 3 months and analyzed. Using the PERC rule with and without the hemoptysis item, there were 13 and 14 missed cases of PE, respectively (failure rate 0.45% [95% CI 0.25%-0.78%] and 0.48% [95% CI 0.27%-0.82%]). Using the YEARS strategy, there were 11 missed PE cases with or without the hemoptysis item (false-negative rate 0.57% [95% CI 0.30%-1.05%]). With the PERC and YEARS rule, removing the hemoptysis item would have led to a 1% reduction in chest imaging. The PEGeD strategy was not modified by the removal of the hemoptysis item. How to cite this article: Bannelier H, Gorlicki J, Penaloza A, et al. Evaluation of the "hemoptysis" item in clinical decision rules for the diagnosis of pulmonary embolism in the emergency department.