BACKGROUND:The study aimed to determine the frequency of enoxaparin dosing errors for patients who had a measured emergency department(ED)weight compared to those who did not have a measured ED weight,and to determine if demographic variables(e.g.,weight,height,age,Englishspeaking,race)impact the likelihood of receiving an inappropriate dose.METHODS:This is a retrospective,electronic chart review of patients who received a dose of enoxaparin in the ED between January 1,2008 and July 1,2013.We identified all patients>18 years who received a dose of enoxaparin while in the ED,were admitted,and had at least one inpatient weight within the first four days of hospitalization.Patients were excluded if they received enoxaparin for prophylaxis or a dose of more than 1.25mg/kg.RESULTS:A total of 1,944 patients were included.Patients were more likely to experience an error if they did not have a measured ED weight.Over-doses of>10mg were more likely to occur in patients without a measured ED weight.Patients with no documented ED weight or with a staffestimated ED weight were more likely to experience a dosing error than those with a patient-stated weight.Patients were more likely to experience an error if their first inpatient weight was more than 96kg,they were more than 175-cm tall,or were English speaking.CONCLUSION:Dosing errors are more likely to occur when patients are not weighed in the ED.Modifications to current workflows to incorporate weighing those patients who receive weightdosed medications may be warranted.